Part three: Countries' experiences in hybrid rice

Status, policies and expectations for hybrid rice research and development in Bangladesh - Matia Chowdhury

Minister of Agriculture of Bangladesh, Dhaka, Bangladesh

The economy of Bangladesh is predominantly agrarian. Situated in the delta of the Bay of Bengal, the country is agroclimatically suited to crop production. With a land area of 147 570 km², the country supports about 132 million people and the annual growth rate of the population is 1.50 percent per annum. About 84 percent of the total population live in rural areas and are directly or indirectly engaged in a wide range of agricultural activities. Agricultural development is, therefore, imperative for reducing poverty and raising the overall living standards of the population.

Agriculture contributes about 31.9 percent to the country's GDP, with 22.9 percent contributed by the crop sector alone. The crop sector employs about 57 percent of the country's total labour force, and accounts for about 90 percent of the agricultural labour force. The fertile land of Bangladesh is used for multiple crops, and around 56 percent of the country's total land area is under crop production. In 1996/97, the net cultivated area amounted to around 7.85 million hectares (Mha) and the gross cropped area was 13.8 Mha.

Rice dominates the crop sector in terms of both production and cultivated land area, accounting for approximately 74 percent of the cropped area. In fact, rice is synonymous of food in Bangladesh and has been the traditional source of carbohydrates and of proteins since prehistoric days. It provides about two-thirds of the average calorie intake. Rice production affects all aspects of life in Bangladesh, particularly the lives of farmers.

Bangladesh has recently achieved good growth in the agriculture sector, due to the increase in food grain production, particularly rice. Thanks to numerous scientific, social and political factors, rice production has been increasing at a very impressive rate. As a result, Bangladesh has gone from a situation of chronic hunger to food self-sufficiency. The increase in rice production is due to a number of factors:

• application of high-yielding varieties developed at Bangladesh Rice Research Institute (BRRI) and other national rice research institutions;

• new agricultural polices and new agricultural extension policy;

• timely supply of inputs; and

• good harvest price.

All these factors have encouraged farmers to make use of their internal potential and resources in order to increase rice production.

Despite the country's food self-sufficiency, factors - such as population growth, loss of biodiversity, erosion, changing environment due to global warming, scarcity of water, soil degradation, urbanization and poor infrastructure - make it difficult to maintain agricultural production at the desired level in a sustainable manner. In order to attain food security for the vast majority of the country's population, the growing demand must be met with less land and water and with limited resources. Shifting the yield frontier with new technology is perhaps the only option available through research and development.

Bangladesh is convinced that hybrid rice is a viable and proven technology representing a new frontier in rice production. Accelerating hybrid rice research and development is a priority of the Government of Bangladesh. Efforts are being made to supply the necessary seed, reduce the cost of F₁ seed production, increase quality, develop pest resistant varieties and improve tolerance to other abiotic stresses. As Bangladesh has no history of hybrid rice development, it has had to learn from the experiences of other countries in order to initiate its own research and development programme.

CURRENT STATUS OF HYBRID RICE RESEARCH AND DEVELOPMENT

The development and use of hybrid rice in Bangladesh began in the early 1990s. Little was achieved in the early stages, but in 1996 hybrid rice research made good progress thanks to the collaboration of the International Rice Research Institute (IRRI). Further support was provided by the Food and Agriculture Organization of the United Nations (FAO) through a Technical Cooperation Programme (TCP) project. The Government identified hybrid rice research as a priority area and established a national research and development network across the country involving public and private sector organizations as well as NGOs.

Initial work on hybrid rice involved tests on F₁ hybrids and evaluation of cytoplasmic male sterile (CMS) and restorer lines received from IRRI. Some Chinese CMS lines and their maintainers were also evaluated for their adaptability and performance in Bangladesh. However, these Chinese lines were not adapted to the prevailing conditions and were highly susceptible to pests and diseases.

A number of IRRI-developed hybrids were tested in multilocation sites for yield potential. Some of these outyielded the standard check variety of the same duration by more than 1 t/ha. Grain quality characteristics of the tested hybrids were comparable with those of the recommended inbred check varieties. Two promising hybrid varieties were included in the national hybrid rice trial during the 1999/2000 boro (winter) season and were subsequently recommended by the National Seed Board (NSB). These two hybrids showed a 1 t/ha yield advantage over the check variety of the same duration in multilocation and on-station trials in various regions of Bangladesh. However, the results were not consistent across locations. The NSB technical committee recommended pilot production programmes for the two proposed hybrid varieties, with a view to recommending them for commercial cultivation in the region where they gave consistently higher yields. Accordingly, a pilot production programme was launched in 2001 with more than 20 plots for each hybrid variety. It is hoped that these two varieties will prove suitable for commercial cultivation in the country.

A comprehensive study of cultural and fertilizer management and pest and disease reaction of promising hybrids and their parental lines is being conducted at BRRI headquarters and regional stations in order to obtain detailed information about the proposed hybrids. During the last three years extensive trials have been conducted on the various aspects of seed production. Progress has been made in hybrid rice seed production, with seed yield increasing from 1.08 to 2.30 t/ha.

Meanwhile, BRRI provided parental materials and a complete seed production technology package of the proposed hybrids to the Bangladesh Agricultural Development Corporation (BADC, a parastatal organization) and to the Bangladesh Rural Advancement Committee (BRAC, an NGO). They produced F₁ seeds of these two hybrids and the seed yield was quite encouraging.

An economic study was undertaken to examine the cost of hybrid rice seed production at the BRRI experimental farm, using both BRRI hybrid experimental plot and farm household data. The output (seed production) of the proposed IR69690H variety (2.30 t/ha) was much higher than that of IR68877H (1.67 t/ha). The total cost (including production and marketing costs) of IR69690H and IR68877H was Tk 51.85/kg and Tk 64.25/kg, respectively^[1].

As part of a short-term programme, the Government allowed four private companies to import heterotic rice hybrid seeds with minimum 1 t/ha increased yield over the best inbred of the same growth duration - on condition that the companies develop the capability to produce hybrid seeds in the country within three years. NSB recommended another hybrid, GB4 (imported by BRAC) for the production of hybrid seeds. The companies eventually managed to produce seeds on their own farms in the 1999/2000 boro season: the seed yield was quite satisfactory.

Technical assistance

Bangladesh maintains close collaboration with IRRI and receives technical and financial support, including seed, materials and training, via the IRRI-ADB (Asian Development Bank) project to establish an effective programme for the research and development of hybrid rice. An FAO TCP project on hybrid rice was launched during 1997-98 and two experts from China were employed to work at BRRI in association with national scientists. A contract research project with support from the Bangladesh Agricultural Research Council (BARC) is being implemented to strengthen research and development in hybrid rice. In addition, South-South Cooperation and TCDC (Technical Cooperation among Developing Countries) programmes provided five Chinese hybrid rice experts to work at BRRI.

A comprehensive national research, seed production and technology transfer programme on hybrid rice was initiated in March 2001 under the PETRRA project funded by the Department for International Development (DFID). In addition, international consultants and experts have been invited to help formulate strategies for the rapid adoption of this technology in the country.

Development of human resources

As part of human resources development in hybrid rice, BRRI has arranged various short- and long-term training programmes. To date, 90 people from public and private organizations and NGOs have been trained at BRRI. Technical back-up support is also provided to NGOs, such as BRAC and GKF (Grameen Krishi Foundation), for hybrid rice research and development and for seeds production. Bangladesh also participates in various international training programmes organized by IRRI, China and India.

STEPS TAKEN (POLICY ISSUES)

The production of hybrid rice - including research - was initiated in Bangladesh only five years ago. The experience and results obtained to date are quite modest, but they have nevertheless created an opportunity for expanding hybrid rice cultivation. Indeed, hybrid rice production is now seen by policy-makers and professionals as the technological breakthrough right for achieving the yield level required to feed the ever-growing population with limited land resources. In the absence of any previous initiative, Bangladesh applied other countries' experience to its own hybrid rice research and development programme.

A national network for hybrid rice has been established at three levels: the Secretary, Ministry of Agriculture (MOA); the Executive Chairman, BARC; and the Director-General, BRRI. A working group on hybrid rice has been formed and includes a plant breeder, seed production specialist, pathologist, agronomist, entomologist and applied research specialists from different government and non-government organizations. BRRI and other national institutions, such as BADC, Bangladesh Agricultural University (BAU), Bangabandhu Sheikh Mujubur Rahman Agricultural University (BSMRAU), as well as NGOs and private sector agencies, are engaged in collaborative research programmes for the production and development of hybrid rice seed.

The Government has adopted a comprehensive master plan on hybrid rice. Accordingly, an action plan has been prepared and boro is the target season for phase 1. BRAC, in association with ACI (a multinational company), is engaged in distributing hybrid seeds in the country. BRAC has its own research and development programme for developing new hybrids and producing hybrid rice seed. GKF is also engaged in the production of hybrid rice seed.

Research institutes and seed-producing agencies are making a concerted effort to formulate an economically viable seed production technology in the country for the rapid adoption and expansion of hybrid technology at farmer level.

Research has produced positive results in vegetative propagation at farmer level, which means that they need not always have to resort to purchasing F₁ seeds. Research is also underway to produce F₁ seeds through "free methods" so that trained farmers can produce their own F₁ seeds. Several R and B lines also have been developed. The R lines may be considered for commercial cultivation as inbred lines.

FUTURE EXPECTATIONS

Despite the progress made so far, there are still many constraints which must be overcome for the large-scale adoption of hybrid rice technology. The adoption of hybrid technology began with the demonstration of related hybrid varieties in 2 000 demonstration blocks (each measuring 5 acres) in the first year. If pursued properly, this could pave the way for taking the technology to between 0.75 and 1.0 Mha by 2010. About one-third of the total rice area in the boro season would then be under hybrid rice cultivation.

The major boro region of the country will be selected in phase 1 of hybrid rice cultivation, where:

• yield plateau is highest;

• risk of crop losses due to aberrant weather is lowest;

• crop diversification is as important as crop intensification;

• pest and disease pressure is minimum; and

• irrigation water is not a limiting factor.

Fifteen such districts are recommended for inclusion in phase 1.

Current manpower levels in the hybrid rice sector are inadequate. A national research team will be formed, research facilities developed and the necessary funds allocated. Institutional linkages among research institutions and seed-producing agencies and companies will be strengthened. The Government is committed to strengthening seed production infrastructure in the public and private sectors and to linking it with hybrid rice breeding institutions, so that the responsibilities for seed production may be shared.

A cheaper seed production package must be developed in order to make the hybrids economically viable for commercial cultivation. The Government is committed to tapping the full potential of hybrid rice technology and will continue to provide the necessary policy support to increase the rate of adoption through large-scale seed production within the country.

Collaboration with international institutes (IRRI, FAO and other related organizations), multinational seed companies and hybrid rice producing countries, will be strengthened to support technology generation, seed production and technology uptake. China has developed super hybrid rice varieties which produce 17 t/ha. Collaboration with China will therefore be strengthened to obtain germplasm with high yield potential.

CONCLUSION

Bangladesh suffered for many years from chronic food deficiency. Despite the adverse natural factors, Bangladesh has recently managed to produce its own food grain using its limited land resources. All efforts are aimed at increasing food production in line with the growing population. The rapid adoption of hybrid technology in large-scale rice production would help achieve this goal. The Government believes in the genuine welfare of the Bangladeshi people, and all actions planned aim to meet the set targets.

Recent progress in the development of hybrid rice in China - Long Ping Yuan

Director General, China National Hybrid Rice Research and Development Center, Changsha, Hunan Province, China

GENERAL SITUATION

In China the total planting area of rice is around 31 million ha (Mha) and the average yield is 6.3 t/ha. The area under hybrid rice accounts for approximately 50 percent of the total rice area and average yield is 6.9 t/ha, while the yield of pure-line varieties is 5.4 t/ha. Hybrid seed production covers around 0.14 Mha and the average yield is 2.5 t/ha.

CONSTRAINTS AND CHALLENGES

There has been no further expansion of the hybrid rice area since 1991. This is the result of two major factors:

• The lack of very early maturity (105-110 days) combinations with good heterosis for the first crop in mid-southern China. In this region, rice is double-cropped and the area under the first crop is approximately 5 Mha (of which hybrid rice covers about 10%).

• The poor heterosis of japonica hybrids (compared to indica hybrids). The yield advantage from growing japonica hybrids is only around 10 percent and purity is also a problem because the male sterility A lines of BT type are not sufficiently stable to produce very pure hybrid seeds. Consequently, farmers are not interested in growing japonica hybrids.

There are 6 Mha of japonica rice in China, but due to the above constraints, japonica hybrids account for only 4 percent of the total japonica rice area. The yield of the existing three-line hybrids, including the more recently developed ones, has stagnated over the years. Furthermore, grain quality needs to be improved to reflect the higher standard of living that Chinese people have become accustomed to in recent years.

RECENT PROGRESS

Two-line hybrid rice has been successfully developed. The planting area of two-line hybrids reached 1.6 Mha in 2000 and over 2.5 Mha in 2001. Generally speaking, yield is 5 to 10 percent higher than in existing three-line hybrids. Very early maturity hybrids with high yield potential and good grain quality have been bred using the two-line method. For example, one hybrid variety (125S/D68), suitable as a first crop in double-cropping regions, was released in 1999. Its planting area soon reached 60 000 ha in 2000 and the average yield was around 7.5 t/ha - outyielding the hybrid CK and pure-line CK by 10 and 20 percent, respectively.

Significant progress has been made in the breeding of super hybrid rice. Two pioneer super hybrid rice combinations have been developed recently (Table 1). Given their high yield potential and good grain quality, the expansion of these super hybrids is very rapid. Planting area will reach 1.7 Mha in 2001.

TABLE 1

Super hybrid rice combinations

SUPER HYBRID RICE BREEDING GOALS FOR 2001-05

Single crop

Large scale: 12 t/ha
Yield potential: 15 t/ha (approx.)
Maximum yield: 18 t/ha

Double crop

• First (early) season
  Large scale: 10.5 t/ha
  Yield potential: 12 t/ha (approx.)

• Second (late) season
  Large scale: 11 t/ha
  Yield potential: 13 t/ha (approx.)

MAJOR EXPERIENCE

Two significant areas have seen major improvements: yield potential and seed yield. In raising yield potential, two important factors come into play:

• development of inter-subspecific (indica/japonica) hybrids to enhance heterosis level; and

• morphological improvement, where the key is to have a huge source based on a large sink of indica/japonica hybrids, i.e. a tall erect-leaved canopy with drooping panicles (such architecture is not only more productive in terms of photosynthesis, but also enables the hybrid to be highly resistant to lodging).

Seed yield is raised through MS lines and through the adoption of improved techniques. In breeding MS lines with high outcrossing rate, the following characters are important:

• early and concentrated blooming on a daily basis;

• high rate of exserted stigma;

• large stigma size; and

• exserted panicles.

The following improved techniques should be applied:

• heavy dosage of GA₃ application;

• increasing row ratio;

• supplementary pollination on time; and

• increasing the number of seedlings per hill for MS lines.

POLICIES PROMOTING HYBRID RICE DEVELOPMENT

Following the great success of large-scale multilocation demonstrations on hybrid rice, at the end of 1975 the Government made an important decision: to provide 8 million yuan (US$4 million) for 4 000 ha of hybrid seed production in Hainam Island in order to accelerate the commercial production of hybrid rice. Tax concessions were granted to seed companies and subsidies were sometimes provided when seed yield was poor during the late 1970s. A well-organized hybrid seed production system was established:

• provincial seed company: responsible for purification of parental lines;

• prefecture seed company: multiplication of A lines; and

• county seed company: F₁ seed production.

The high level research institute, the China National Hybrid Rice Research and Development Center, was established. There are eight senior plant breeders, five agronomists, four seed production experts and four biotechnology scientists.

Status of hybrid rice development in India - Chitta R. Hazra

Agriculture Commissioner of the Government of India Ministry of Agriculture, Department of Agriculture and Cooperation, New Delhi, India

INTRODUCTION

Rice plays a fundamental role in Indian agriculture as it is the staple food for more than 70 percent of the population and the source of livelihood for 120-150 million rural households. It accounts for 43 percent of food grain production and 55 percent of cereal production in the country. At the current rate of population growth (+1.8%) the rice requirement will be around 140 million tonnes (Mt) by 2020. Rice in India is currently grown on about 44.6 million ha (Mha), of which about 91 percent is cropped during the monsoon (kharif) season (June-Nov.) and the rest during the winter/summer (rabi) season (Dec.-May). However, crop productivity during the rabi season is much higher, accounting for about 15 percent of total rice production. Rice is grown in every state. Rice production in 1999/2000 was about 89.5 Mt.

Given the huge advances in rice production during the 1960-1980 Green Revolution (characterized by semi-dwarf high-yielding varieties and associated improved management practices) and the decelerating trend in productivity over the last decade, a much higher yield accelerating technology is called for. Achieving the productivity targets in the next few decades is a challenge as the productivity increase must come from a resource base which is declining and degrading in terms of land, water, labour and other inputs, without harming the environment. Of the genetic options available for raising the yield ceiling further, hybrid rice - as has been successfully demonstrated in the People's Republic of China - appears to be the most feasible and readily adaptable technology.

HYBRID RICE RESEARCH PROGRAMME

Recognizing the potential of hybrid rice technology as a proven means to enhance production and productivity, the Indian Council of Agricultural Research (ICAR) initiated a goal-oriented project on hybrid rice together with other crops in 1989. This project was further strengthened with support from the United Nations Development Programme (UNDP, 1991-96) which provided consultancy and training fellowships and procured the necessary equipment. The Mahyco Research Foundation, a non-profit agency, has also helped ICAR fill some critical gaps.

Network

The hybrid rice project functions as a national network with 12 centres spread across the country and the Directorate of Rice Research (DRR, Hyderabad) is the coordinating centre. Each centre in the network is assigned specific responsibilities, such as the development of Basmati hybrids (New Delhi), hybrids for shallow lowlands (Cuttack) or long duration hybrids suitable for coastal regions (Maruteru). Other centres are developing region-specific hybrids. The hybrids developed at various centres and received from the International Rice Research Institute (IRRI, Philippines) are pooled together for critical evaluation. Seed production agencies, both public and private, have been actively involved in the network from the very beginning. This has helped motivate several private companies which now produce the bulk of the nation's hybrid seed. This well-organized network approach is one of the key factors for the successful implementation of the hybrid rice project.

Objectives

The main project objectives are:

• development of hybrids with 15-20% yield advantage over the highest-yielding check varieties;

• optimization of the seed production package;

• standardization of the production package for the cultivation of hybrids; and

• execution of basic research relevant to the project goals.

Coordinated efforts

The concerted efforts of all concerned, the timely support of national and international agencies (e.g. UNDP, IRRI and FAO), effective networking and regular monitoring of the project have contributed to the remarkable progress made during the last decade. The hybrid rice project launched by ICAR motivated various stakeholders and helped the country enter the era of hybrid rice.

RELEASED HYBRIDS

As a result of the systematic evaluation of experimental hybrids in multilocation trials, 12 hybrids have been developed by the research network centres and released by the respective State Variety Release Committees (SVRC). The details on hybrids released to date are given in Table 1. Hybrid PHB 71 (developed by Pioneer Overseas Corporation, a private company) was released by the Central Variety Release Committee (CVRC), and hybrid PA 6201 (developed by Pro Agro Seeds, a private company) was also released. They were released for use in more than one state, while other hybrids are state-specific.

TABLE 1

Hybrids released in India

^a OFT = On-Farm Trials.

Prior to launching the hybrid rice project, neither usable CMS (cytoplasmic male sterile) lines nor rice hybrids were available in the country. Within five years of the start of the project, four hybrids were released (in 1994). Nine more hybrids were released between 1995 and 1998 and one during 2000, giving farmers a wide selection of hybrids suitable for their own region.

Frontline demonstrations are performed by scientists for the propagation and popularization of released hybrids.

DEVELOPMENT OF HYBRIDS

Development and evaluation of hybrids is one of the major objectives of the hybrid rice development programme. Hybrids developed by the network centres, and those received from IRRI or contributed by private sector seed agencies, are systematically evaluated in multilocation trials. Hybrids that show good results in multilocation national hybrid rice trials for three seasons are further evaluated in farmers' fields in target areas to reconfirm their superiority, before being released for commercial cultivation. Consistent performance in different locations and seasons is the most desirable feature of any hybrid as it is an indication of yield stability.

Evaluation of hybrids for rainfed lowlands

Initially, hybrid rice cultivation was targeted at high productivity irrigated areas in Andhra Pradesh, Karnataka, Tamil Nadu, Punjab, Haryana, Uttar Pradesh and Maharashtra. With 10 Mha of rainfed shallow lowlands, the development of hybrids for this ecosystem is also a priority. Most of the hybrids producing higher yields under irrigated environments have also shown their yield advantage in rainfed shallow lowlands.

Development and evaluation of Basmati hybrids

India is renowned for its production and export of high quality Basmati rice. Since the yield of Basmati varieties is generally low, development of Basmati hybrids will greatly help to improve yields. A number of experimental Basmati hybrid rice varieties are being tested in the major Basmati rice-growing areas of the country: Punjab, Haryana and Western Uttar Pradesh.

Participation of the private sector

India has a strong and well-organized private seed industry and many seed companies have their own research and development departments. Public and private research have the common objective of popularizing hybrid rice. Private companies produce and market seed, and some also develop hybrids, which they have been nominating for evaluation since 1992. To date, 12 companies have nominated hybrids for trials; the most important are Pioneer Overseas Corporation, Pro Agro and Mahyco.

Evaluation for quality characteristics of hybrids

Rice is used almost exclusively as a food product. Cooking and eating quality traits therefore assume special significance. For general consumer acceptance, it is essential that the hybrids developed possess good quality characteristics as well as high yield potential. Therefore, the hybrids included in trials and parental lines have been critically screened for various quality parameters. Preferences for quality vary from region to region. A variety or hybrid liked in one region may not be liked in another. Therefore, it is imperative to bear in mind local preference when developing hybrids.

Grain shape and appearance, milling and head rice recovery, amylose content and gelatinization temperature (alkaline value) are some of the parameters that influence the cooking and eating qualities of rice. All hybrids released, including those marketed by the private sector, were evaluated for quality traits. A good quality hybrid has:

• head rice recovery of over 55%;

• intermediate amylose content (20-25%);

• intermediate alkaline value (4.0-5.0); and

• translucent grains without chalkiness.

Most of the released hybrids have long slender to medium slender grains; a few have long bold grains. Head rice recovery of the hybrids ranges from 51.5 to 68.0 percent and most of the hybrids have head rice recovery of more than 55 percent. Some hybrids, such as DRRH-1, ADTRH-1, PHB-71 and PA-6201, have intermediate amylose content and intermediate alkaline value. Some hybrids have intermediate amylose content (NSD - 2, MPH 519, PAC 801 and VRH 704), while others have intermediate amylose content and alkaline value (KRH-1, CORH-2, MPH-517). Sambha Maheshwari - a popular variety - is also characterized by intermediate amylose content and alkaline value. Interestingly, water uptake of this variety is very low (165 ml), which is distinctly different from other varieties and hybrids. This suggests that low water uptake is an indication of better cooking quality.

SEED PRODUCTION OF HYBRID RICE IN INDIA

Besides high level of heterosis, the other essential requisite in hybrid rice development is seed production (an important component of any hybrid technology). Important factors in the seed production package include: isolation distance, synchronization between parental lines, optimum seeding intervals, planting pattern, ideal row ratios, dose and time of GA₃ application, and supplementary pollination techniques. Extensive trials were conducted in different network centres and interproject linkages have been established with the National Seed Project (NSP). These combined efforts have helped to optimize a seed production package with which seed yields of 1.0 to 1.5 t/ha may be obtained.

Parental lines of most of the hybrid combinations differ in their flowering duration and it becomes increasingly important to obtain perfect synchronization between parental lines. This is one of the problems most commonly encountered by seed growers, especially in the initial years, and it needs special consideration.

The first step to ensure proper synchronization between parental lines is to determine the difference in flowering duration between the two lines (known as seeding interval). Seeding interval is generally determined by evaluating:

• Growth Duration Difference (GDD);

• Leaf Number Difference (LND); and

• Effective Accumulated Temperature (EAT) differences.

Row ratio (i.e. male parent: female parent rows in a seed production plot) is an important factor influencing the extent of seed-set and the seed yield. Seed yield also depends on row direction, panicle structure and the pollen load of restorer lines. The extent of outcrossing in seed production plots depends on panicle exsertion (%), stigma exsertion (%), the size and alignment of flag leaf, and the pollen load of pollen parents.

Most of the indica/indica hybrids developed in India and elsewhere are based on CMS lines with "WA" backgrounds. Incomplete panicle exsertion in almost all the "WA" base CMS lines is one of the major obstacles to higher seed yields, as between 20 and 30 percent of the panicles are enclosed in the flag leaf and the enclosed spikelets are not available for cross pollination. To overcome this problem, experiments were conducted to optimize the dose of GA₃ or find an alternative in view of its high cost.

Creating awareness of the benefits and imparting the necessary skills to farmers are an important prerequisites for the large-scale adoption of any new technology, and hybrid rice is no exception. Hybrid seed production is a complicated process and seed production personnel and seed growers need to receive proper training. Training programmes were therefore organized for public and private sector seed agency staff, seed growers and farmers (men and women). Similarly, short-duration training courses on hybrid rice cultivation were organized at different centres for the benefit of the farmers.

Two-line heterosis breeding

The discovery of environment-sensitive genic male sterility (EGMS) in rice led to the development of a simple and efficient two-line hybrid breeding system, thus overcoming the major limitations of the three-line approach, namely: restrictions on the availability of parental lines, negative effects associated with sterility-inducing cytoplasm, limited yield advantage and complicated seed production processes. Experience in China revealed the yield advantage of intervarietal two-line hybrids over the ruling three-line hybrids to be between 5 and 10 percent. Therefore, the deployment of a two-line system for developing intervarietal and inter-subspecific hybrids holds great promise.

The two-line approach includes:

• use of EGMS; and

• use of chemically induced male sterility.

In India research in these areas was initiated a few years ago.

EGMS includes photoperiod-sensitive genic male sterility (PGMS), thermo-sensitive genic male sterility (TGMS) and sterility induced by the interaction between photoperiod and temperature. PGMS is not suitable, as the required day-length differences do not exist in the Indian subcontinent. The temperature ranges available are suited to the TGMS system. The main emphasis was therefore placed on the identification and characterization of TGMS sources.

The first stage in two-line breeding is to characterize the TGMS lines for their critical sterility- and fertility-inducing temperature regimes. Work on the characterization of TGMS lines was undertaken at different network centres. In the last eight years, several male sterile plants suspected of carrying temperature-sensitive genes were isolated from germplasm collections, breeding nurseries, farmers' fields and mutagen-treated populations.

Breeding for indica x japonica hybrids

The yield advantage of the present day intervarietal rice hybrids in China and elsewhere is between 15 and 20 percent. In order to make hybrid rice cultivation a highly profitable and attractive enterprise, it is necessary to further increase heterosis. It is a well-known fact that the magnitude of heterosis depends on the hybrid combination, as follows:

indica x japonica > indica x indica > japonica x japonica

The indica x japonica hybrids are known to give 15 to 20 percent yield advantage over indica x indica rice hybrids. Early attempts in the 1960s to combine the good characters of indica and japonica varieties met with little success because of inherent sterility problems. With the discovery of the wide compatibility gene (WC), it became possible to develop normal fertile indica x japonica F₁ hybrids. However, such F₁ hybrids are not without problems, for example: improper grain filling, poor grain quality, asynchrony in flowering (time of day) of indica and japonica parents, undesirable plant height, and low level of resistance to insect pests and diseases. It is therefore necessary to breed improved japonica for use in the development of inter-subspecific hybrids.

AVAILABILITY OF HYBRID RICE SEEDS

Propagation of hybrid rice is to a great extent dependent on the availability of hybrid seeds. Public-bred hybrid seeds account for just 12 000 to 13 000 ha. In recent years, the public seed-producing agencies have produced about 200 tonnes of certified hybrid rice seeds annually, while private sector companies produce about 2 900 tonnes. Together they cover an area of 150 000 ha, as some seeds are also exported. Effort is therefore required to substantially increase the production of hybrid seeds and expand the area under hybrid rice. The average yield advantage from hybrid seeds is between 10 and 15 percent at national level, which in terms of physical yield is about 1 t/ha.

The main obstacle to the widespread adoption of this technology is the availability of hybrid seeds (the national production of hybrid seeds is between 0.8 and 1.5 t/ha). Furthermore, farmers are reluctant to accept the technology because hybrids have quality limitations, such as stickiness and an aroma which is not to the liking of consumers. The price fetched for hybrid rice can be below that of normal traditional varieties, which means that the benefits of increasing productivity by 15 to 20 percent are therefore often nullified by the decrease in value. The challenges therefore faced by this technology are to:

• achieve the high quality demanded by consumers; and

• increase productivity of hybrid seeds (which are 5 to 6 times more costly than traditional varieties).

These issues must be addressed for the proliferation of hybrid rice technology in India.

FUTURE THRUST AREAS

• For the large-scale adoption of this technology, it is necessary to increase awareness of and demand for hybrid rice seeds. This is possible through extensive on-farm trials, frontline demonstrations and training programmes on hybrid rice technology

• It is important to perfect seed production technology in order to achieve higher seed yields of F₁ hybrids, thus reducing seed cost and increasing availability.

• Emphasis must be placed on the improvement of cooking and eating quality to satisfy consumer preference.

• It is important to incorporate resistance to major pests and diseases.

• Priority must be given to the development of rice hybrids for different ecosystems, especially shallow lowlands, which are similar to the irrigated ecosystem.

It is essential to communicate the benefits and transfer the technology to the end users. This may be achieved through demonstrations, training programmes and field visits for the benefit of the farming community. The commitment of extension agencies is crucial. Despite initial problems, appropriate policies and the active involvement of researchers, seed producers and extension specialists can certainly lead to the rapid coverage of hybrid rice in India in the coming years.

Strengthening the development and use of hybrid rice in Indonesia - Andi Hasanuddin^a and Tarkim Suyitno^b

^a Director, Central Research Institute for Food Crops, Agency of Agricultural Research and Development, Bogor, Indonesia
^b Director, Seed Development, Directorate General of Food Crop Production, Jakarta, Indonesia

INTRODUCTION

Achieving food security through increasing rice production is a major challenge for agricultural development in Indonesia. Following the yield increases obtained with the semi-dwarf variety, IR8, yield potential has shown a plateauing trend. The exploitation of heterosis using hybrid varieties resulted in an increase in yield of 15 to 20 percent over high-yielding inbred varieties under farmers' field conditions in China, India, Viet Nam and the Philippines. A similar yield increase was exhibited in hybrid rice trials in Indonesia. However, there were constraints: yield instability, susceptibility of most hybrids to major pests and diseases, and shortage of hybrid seed.

A number of promising hybrids with high yield potential and moderate resistance to brown planthopper (BPH) and bacterial leaf blight (BLB) have been identified recently. These hybrids should be evaluated for yield stability, adaptability and other important characters. An intensified breeding programme is required to develop improved hybrids.

STATUS OF HYBRID RICE RESEARCH

Hybrid rice research and development activities were initiated in Indonesia in 1983. Activities focused on the evaluation of hybrids and parental lines introduced from China and other countries. The success of hybrid rice development in some countries outside China, including India, Viet Nam and the Philippines, encouraged the Government of Indonesia to intensify research and development of hybrid rice in the country. Recent activities have been conducted by the Research Institute for Rice of the Central Research Institute for Food Crops, the Directorate of Seed Development and some private seed companies.

Hybrid rice research and development in Indonesia receives technical support from the International Rice Research Institute (IRRI). A Technical Cooperation Project sponsored by FAO to strengthen the development and use of hybrid rice in Indonesia is being implemented.

Evaluation of CMS lines

Many CMS (cytoplasmic male sterile) lines have been evaluated in Indonesia since 1983. The first evaluation was done on CMS lines introduced from China, including ZS97A, V20A, V41A, Er Jiu Nan 1A and Wu 10A. They were found to be less stable in pollen sterility and susceptible to major tropical pests and diseases, particularly bacterial leaf blight. They were, therefore, not suitable for the development of hybrid rice varieties in Indonesia.

CMS lines provided by IRRI and periodically introduced to Indonesia were evaluated. Most CMS lines have one or more of the following undesirable characteristics: unstable pollen sterility; susceptibility to major pests and diseases; poor combining ability; and low outcrossing rate. However, some CMS lines with high and stable sterility, good agronomic characteristics (such as early to medium maturity), medium plant height, uniformity and moderate resistance to bacterial leaf blight, have been identified (Table 1). They showed 100 percent pollen and spikelet sterility, required about 84 days for 50 percent flowering, and had moderate level of resistance to bacterial leaf blight. CMS lines: IR58025A, IR62829, IR68886 and IR68897 were found promising and have been used to develop hybrids with restorer lines of locally bred varieties or breeding lines. Efforts to develop new CMS lines and restorers using IRRI material and local germplasm through backcrosses were intensified in 1998.

Evaluation of F₁ hybrids

In most of the yield trials conducted, F₁ hybrids consistently yielded more than the best check variety (Table 2). Most of the hybrids derived from IR58025A produced high yield, indicating that this CMS line has good general combining ability. It also possesses desirable characters, such as pleasant aroma, good grain quality and moderate resistance to some major pests and diseases.

TABLE 1

Selected CMS lines with high and stable sterility and desirable agronomic characteristics^a

^a Average data of three testing sites, Cianjur, Purwokerto and Kuningan.

TABLE 2

Summary data of replicated yield trials on hybrid rice conducted in Indonesia, 1990-96

Several promising combinations have been selected based on the performance of the corresponding F₁ hybrids in the yield trials. Selected combinations were IR59025A/IR53942, IR59025A/BR827, IR59025A/IR54852, IR58025A/IR64, IR62829A/BR827 and IR59025A/IR72. In yield trials conducted in Sukamandi, Kuningan and Tegalgondo, the selected F₁ hybrids yielded 20 to 40 percent more than the check variety, IR64. In addition, the hybrids have early to medium maturity, medium plant height, moderate resistance to BPH and BLB and good grain quality.

On the basis of characteristics and outcrossing rate in hybrid seed production, three promising hybrids were selected: IR59025A/BR827, IR59025A/IR53942 and IR62829A/BR827. Multilocation yield trials were conducted in seven sites (Sukamandi, Subang, Tajum, Kulonprogo, Klaten, Ngawi and Kediri) during the 1999/2000 wet season. The hybrids exhibited unstable yield and inconsistent heterosis across locations (Table 3). IR58025A/BR827 showed 14.6 and 17.7 percent heterosis in Tajum and Kulonprogo, respectively, but in other locations heterosis was lower or even zero. IR58025A/IR53942 showed high heterosis only in Tajum. IR62829A/BR827 showed 10 and 15 percent heterosis in Sukamandi and Klaten, respectively. The heterosis expression of the hybrids was affected by genetic-environment interaction. Therefore, identification of the appropriate area is important prior to release for commercial cultivation.

Following test crosses and combining ability studies utilizing IRRI-bred CMS lines and local germplasm, a number of hybrids were selected. In the observation trials, most of the hybrids yielded over 7 t/ha, whereas the check varieties, IR64 and Widas, yielded 6.20 and 6.45 t/ha, respectively (Table 4). The hybrids showed higher spikelet fertility but more filled grains per panicle compared to the check variety.

Seed production

Experiments to increase the efficiency of hybrid seed production have been conducted. Several treatments, including chemicals (to increase panicle exsertion, population or row ratio between male and female parents) and cutting of flag leaves, have been applied. However, the hybrid rice seed yield remains low and unstable.

TABLE 3

Yield performance of the promising hybrids and check varieties tested in 7 locations, wet season 1999/2000

Note: Figures in brackets indicate percentage increase over check yield.

TABLE 4

Selected hybrids from observation nursery, wet season 2000/01

In experimental plots of hybrid rice seed production, 20 to 30 percent seed-set with a yield of 1.0 to 1.5 t/ha was obtained (Table 5). In larger plots, however, the seed yield was very low, less than 0.5 t/ha (Table 6). The major constraints to high yield in hybrid rice seed production were: unsynchronized flowering between the parental lines and impurity of the seed used. It was observed that the flowering date was affected by environmental factors, such as temperature and light intensity, as well as by cultural practices. Locations suitable for seed production are currently being identified. An isolation facility for producing nucleus and breeder seed was established for producing pure seed of the parental lines. A small quantity of nucleus and breeder seed of the promising parental lines, IR58025A and IR62829A, together with their corresponding maintainer and restorer lines was produced for further multiplication.

TABLE 5

Maximum seed yield obtained in different seed production experiments on parental lines and hybrids

TABLE 6

Seed production of hybrids and CMS lines, wet season 1998/99 and dry season 1999

POLICIES AND EXPECTATIONS

Indonesia achieved self-sufficiency in rice in 1984 through the adoption of high-yielding varieties. There was productivity growth of about 5 percent and rice production reached 40 million tonnes (Mt). During the past five years the productivity growth rate has decelerated to 0.1 percent with production stagnating at around 50 Mt and the Government of Indonesia (GOI) has been compelled to import 1 to 3 Mt of rice a year. The current varieties and technology available are unlikely to produce further yield increase. The area under rice cultivation tends to decrease due to competition from more economical crops and non-agricultural activities.

Hybrid rice's great success in increasing rice yield in China, followed by India, Viet Nam and the Philippines, encouraged the Government of Indonesia to develop the technology. Most of the rice-cultivated area in Indonesia is under irrigated land with a high man-land ratio suitable for the adoption of hybrid rice technology.

Hybrid rice research has been conducted in Indonesia since 1983. However, no hybrid variety has yet been commercially released due to one or more of the following constraints:

• instability of parental line sterility;

• instability of heterosis expression;

• susceptibility to major pests and diseases of the hybrids; and

• low yield of hybrid seed.

To expedite the development and use of hybrid rice technology, the Government of Indonesia adopted the following policies:

• strengthening of hybrid rice research and development;

• establishment of a national committee for hybrid rice;

• establishment of a seed system for hybrid rice; and

• encouraging the private sector, including seed companies, to develop and market hybrid rice seed in Indonesia in collaboration with donor countries and international agencies.

Since 2000, the Government of Indonesia has increased the funds for hybrid rice research and development. Breeding has concentrated on the development of adapted hybrid varieties with resistance to major pests and diseases and acceptable grain quality. Research has focused on improving cultivation techniques, seed production and the socio-economic aspects of hybrid rice.

FAO has provided support through project TCP/INS/8921, "Strengthening the Development of Hybrid Rice in Indonesia". The objective of this project is to strengthen the national capacity in hybrid rice technology through:

• a national and international training programme;

• the development of infrastructure; and

• international training in hybrid rice by TCDC (Technical Cooperation among Developing Countries) experts and consultants.

Hybrid rice research and development has also been conducted in collaboration with some Asian countries, IRRI and ADB. The activities of the project have focused on germplasm exchange and other breeding aspects for the development of hybrid rice varieties.

INTERNATIONAL CONSULTANTS AND EXPERTS AND TRAINING PROGRAMMES

International consultants/TCDC experts

As per the proposed plan of action, international consultants and TCDC experts were appointed by FAO with the agreement of the Government of Indonesia, as follows:

• Dr K. Krishnaiah, Senior Consultant/Team Leader

• Dr Y. Yogeswara Rao, TCDC Expert/Consultant on Hybrid Rice Seed Production

• Dr B.C. Viratamath, TCDC Expert/Consultant on Hybrid Rice Breeding

Training programmes

Hybrid rice is a new technology involving special skills in breeding, seed production and cultivation. Intensive training is therefore required in all these activities. A very limited number of scientists from the Agency of Agricultural Research and Development and two staff members from the Directorate General of Food Crop Production have been exposed to the technology. Training is therefore needed for breeders and senior seed production personnel - either abroad or within the country - for around four months during the crop season. It is important to train extension workers and farmers involved in hybrid seed production and cultivation by bringing them to the seed farms during critical operations or at least three times during the crop season. It is imperative to expose policy-makers and senior administrative functionaries to the progress made in China, India and Viet Nam and at IRRI.

The training programmes are as follows:

In-country training

• Wet season planting 2000/01 (executed):

  - Seed production specialists - 30 people, 15 days
  - Seed producers/farmers - 80 people, 2 days
  - Extension workers - 50 people, 3 days

• Dry season planting 2001 (planning):

  - Breeders - 15 people, 10 days
  - Seed production specialists - 15 people, 10 days
  - Seed producers/farmers - 40 people, 2 days
  - Extension workers, seed certification staff - 30 people, 3 days

Overseas training to China, 3.5 months

- Breeder - 1 person (in progress)
- Seed production - 2 people (in progress and executed)

Study tours - 3 people (in progress)

For a 2-week period, 1 person in May/June 2001, 2 people in September 2001.

PRIVATE SECTOR

The involvement of the private sector in hybrid rice in Indonesia is as follows:

• PT BISI - development of hybrid rice breeding in Indonesia

• PT Pioneer - introduction of hybrid rice from India and the Philippines

• PT Sutowido - introduction of hybrid rice from India

• PT Kondo - introduction of hybrid rice from Japan

• PT Monsanto - introduction of hybrid rice from India and the Philippines

• PT Bibit Baru - introduction of hybrid rice from China

ESTABLISHMENT OF SEED SYSTEM FOR HYBRID RICE

Indonesia has an established seed system for inbred rice - including seed production, distribution, marketing and quality control - capable of providing an adequate supply of high-yielding varieties. The system includes:

• National Seed Board - advice on seed policy to the Minister of Agriculture;

• Research Institute for Rice - breeding and production of breeder seed;

• Seed Control and Certification Service - ensuring high quality of seed for production, distribution and marketing;

• seed farms - production and distribution of foundation and stock seeds;

• national seed companies (PT Sang Hyang Seri and PT Pertani) - production, distribution and marketing of seed; and

• private seed companies and growers - production and marketing of seed.

Seed production for hybrid rice, including seed production of parental lines and F₁ hybrids, is different from seed production for inbred varieties. Studies are underway to assess the capability of the system and the necessary adjustments for application to hybrid rice.

IMPACT OF HYBRID RICE DEVELOPMENT ON NATIONAL RICE PRODUCTION

Rice production in Indonesia has fluctuated over time by about 1 to 2 Mt a year. In 2000, rice production had a surplus of 1 Mt, but for 2001 a deficit of 2 Mt is expected. The deficit and surplus are considered relatively small compared to 50 Mt of domestic rice production. These deficits or surplus are considered high in terms of volume, because the ability to provide storage is very limited.

Considering the biophysical and management constraints of hybrid rice development in Indonesia, it is estimated that by 2004 the target of 1 million ha (Mha) and 1 Mt of additional rice production will be reached (Table 7). The additional 1 Mt will make an important contribution to overcoming the national rice deficit.

The seed production costs of hybrid rice are higher than for inbred rice: Rp 7 million and 4 million per ha, and Rp 7 000 and 1 335 per kg for hybrid and inbred seed, respectively. The total revenue is estimated at Rp 3 million and 3.5 million per ha (Table 8).

TABLE 7

Hybrid seed and rice production target, 2001-04

TABLE 8

Input-output analysis of hybrid rice seed production

Note: US$1 = Rp 9 000.

Table 9 shows approximate production costs and returns for hybrid and inbred rice production.

TABLE 9

Input-output analysis of hybrid rice production

Note: US$1 = Rp 9 000.

CONCLUSION

Rice is the staple food of most Indonesians. Rice production should be increased to meet the demands of the growing population. Two important components of rice production are the planted area of improved rice varieties and rice productivity per unit area.

The rice area cannot be expanded due to the limited land and water availability. Therefore, an alternative approach to increasing rice production is raising the yield potential. It is known that the heterotic effect of hybrid rice increases yield by about 20 percent over high-yielding inbred varieties. This heterotic effect represents an opportunity to increase rice productivity and rice production.

Research and development in hybrid rice was initiated in 1983 by the Research Institute for Rice (RIR) of the Central Research Institute of Food Crops (CRIFC) with the technical support of IRRI. Also involved in hybrid rice development is the Directorate of Seed Production with the support of FAO.

Research on hybrid rice development has aimed at the development of a hybrid rice variety with a yield potential 15 to 20 percent higher than the yield of improved inbred rice. Promising hybrid rice varieties identified so far, such as IR59025A/BR827, IR59025A/IR53942 and IR62829A/BR827, have exhibited unstable yields and inconsistent heterosis across locations.

Further constraints to hybrid rice development exist in hybrid seed production, which is low and unstable below 1 t/ha. The major constraints to hybrid rice seed production are unsynchronized flowering between parental lines and seed impurity. In a tropical country like Indonesia, rice flowering is greatly affected by temperature, light intensity and cultural managements.

Hybrid rice research and development continue with the strengthening of breeding work. The programme for the coming years includes:

• development of hybrid rice with 15 to 20 percent higher grain yield than inbred varieties;

• identification of potential areas for hybrid rice growing;

• development of improved cultural management;

• improved technology generation for hybrid seed production; and

• development of hybrid seed systems.

REFERENCES

Satoto & Suprihatno, B. 1992. Pengaruh zat pengatur tumbuh terhadap pembentukan biji dan hasil benih galur mandul jantan. Media Penelitian Sukamandi, 12: 10-12.

Satoto, Suprihatno, B. & Sutaryo, B. 1994. Heterosis dan variasi genetik berbagai karakter hibrida padi. Media Penelitian Sukamandi, 15: 6-11.

Suprihatno, B. & Satoto. 1986. Vigor hibrida untuk hasil dan komponen hasil beberapa kombinasi F₁ hibrida. Media Penelitian Sukamandi, 3: 5-12.

Suprihatno, B. & Satoto. 1989. Ratio barisan dan pengguntungan daun bendera pada perbanyakan benih galur mandul jantan V41A dan MR365A. Media Penelitian Sukamandi, 7: 31-34.

Suprihatno, B. & Satoto. 1998. Research and development of hybrid rice technology in Indonesia. In S.S. Virmani, E.A. Siddiq & K. Muralidharan, eds. Advances in hybrid rice technology. p. 413-420. Proceedings third International Symposium on Hybrid Rice, Hyderabad, India, 14-16 Nov. 1996. Manila, Philippines, IRRI.

Suprihatno, B. & Silitonga, S. 1988. Suitability of seed production technologies in Indonesia. In Proceedings of Symposium on Hybrid Rice, Changsa, China, 6 - 10 Oct. 1986. p. 274-275. Los Baños, Philippines, IRRI.

Suprihatno, B., Sutaryo, B. & Silitonga, T.S. 1994. Hybrid rice research in Indonesia. Hybrid rice technology: new development and future prospects. In Selected papers from the International Rice Reseach Conference. p. 195-205. Manila, Philippines, IRRI.

Suprihatno, B., Sutaryo, B., Satoto, Yuniati, P.M. & Utomo, S.T.W. 1998. Hasil-hasil penelitian padi hibrida di Indonesia. Makalah sisampaikan pada seminar Programme Produksi Benih Padi Hibrida, Jakarta, 29 Dec. 1998. 20 pp.

Sutaryo, B., Baihaki, A. Harahap, Z. & Suprihatno, B. 1990. Pengaruh hormon GA₃, pengguntingan daun bendera, dan perbandingan baris tanaman mandul jantan sitoplasmik genetik dengan pemulih terhadap benyaknya benih padi hibrida. Media Penelitian Sukamandi, 8: 1-4.

Sutaryo, B. & Suprihatno, B. 1992. Pengaruh GA₃, pengguntingan daun bendera dan perbandingan baris tanaman terhadap hasil dan komponen hasil pada benih galur mandul jantan padi IR62829A. Zuriat, 3(2): 7-15.

Hybrid rice programme in the Philippines - Edmund J. Sana,^a Frisco M. Malabanan^b and Edilberto D. Redoña^c

^a Assistant Secretary for Field Operations, Department of Agriculture, Quezon City, Philippines
^b Program Director, Ginintuang Masaganang Ani Rice Program, Department of Agriculture, Maligaya, Philippines
^c Program Leader, Hybrid Rice Program, PhilRice, Maligaya, Philippines

INTRODUCTION

Under the Department of Agriculture's Agrikulturang MakaMASA programme, hybrid rice technology has been demonstrated to increase rice yields by an average of 15 to 25 percent over the best modern varieties available nationwide. In large-scale demonstration trials conducted from 1998 to 1999 across the country, the rice hybrids, PSB Rc26H (Magat) and PSB Rc72H (Mestizo), outyielded the best inbred varieties by 0.78 to 1.27 t/ha (Table 1). This increase in rice production has the potential to eliminate most of the annual rice imports.

The technology requires a different system of seed production (Figure 1 and Table 2); more labour is therefore needed and employment opportunities are generated in rural areas. It also offers higher income opportunities for farmers, either through F₁ cultivation or hybrid seed production. Farm incomes will increase by 2.43 to 11.84 billion pesos, with hybrid rice farmers earning an average extra income of 6 800 to 8 800 pesos/ha. Hybrid seed growers who produce at least 1t/ha of F₁ seeds earn 44 000 pesos/ha more than inbred rice seed growers (Table 3).

At present, 50 percent of the rice produced in China comes from hybrid rice. Viet Nam and India have also increased their hybrid rice areas to 200 000 and 300 000 ha, respectively. The use of hybrid rice in these countries has been strongly supported by major investments in hybrid rice research, development and extension (RD&E), by both the public and the private sector. In the Philippines, a comprehensive hybrid rice programme (HRP) was initiated in 1998 to strengthen the national capacity for hybrid rice development and use.

TABLE 1

Yields of the Magat and Mestizo hybrids in the technology demonstration trials conducted nationwide under the Agrikulturang MakaMASA programme, 1998-99

TABLE 2

Seed production processes needed to commercialize F₁ hybrid cultivation

TABLE 3

Profitability analysis of hybrid rice and inbred rice cultivation and seed production in pesos^a

^a US$1 = 45 pesos approx.(at time of writing).
^b Based on 20-ha technology demonstration trials, 1998 DS.
^c Estimated yield of inbred seed production.
^d Includes the R line harvested at 2 t/ha.
^e Return on investment.

During the first two years of implementation (1999-2000), the HRP implemented 18 RD&E projects, with a total of 91 studies carried out by 85 leading scientists and technical personnel. Activities centred on areas, such as: germplasm conservation, varietal development, biotechnology, planting, nutrients, water and pest management, engineering and mechanization, socio-economics and seed production.

Training courses, workshops, technology demonstrations and other information-generating activities were also carried out under the allied Technology Promotion Program of PhilRice. A PhilRice Hybrid Rice Center, based in San Mateo, Isabella was also established to serve as the fulcrum for applied hybrid rice RD&E.

Technical collaborative activities were established and implemented with:

• countries, such as China, Viet Nam, and India;

• local institutions, such as the International Rice Research Institute (IRRI) and the University of the Philippines in Los Baños (UPLB); and

• private companies, such as Agroseed, Hyrice, Aventis CropScience and Hybrid Rice Seed Entreprises (a Division of SL Agritech).

FIGURE 1 The seed production system required for commercialization of hybrid rice technology

Support for the HRP was obtained from the Department of Agriculture, IRRI, the Asian Development Bank, the Rockefeller Foundation and the Food and Agriculture Organization of the United Nations (FAO). In a national hybrid rice review and planning workshop held in November 2000, the continuing need for a hybrid rice RD&E programme was again stressed; the needs, issues and constraints for hybrid rice technology generation, seed production and technology promotion were identified; and solutions to problems were proposed. After two years of implementation the HRP was streamlined and refocused, not only to address current issues, but also to operationalize strategic initiatives in view of the projected increase in farmer demand for hybrid rice technology. At the beginning of the 2001 dry season, 10 000 ha of irrigated rice land will be planted to hybrid rice in Region 2 alone. The hybrid rice area is expected to increase by up to 400 000 ha by 2004. Ultimately, the HRP expects to make a significant contribution to the national goal of attaining self-sufficiency and food security (Redoña, 2000).

OBJECTIVES

• Supply seed growers' A line and R line requirements for large-scale AxR seed production.

• Produce the highest quality of parental line seeds for use in large-scale hybrid seed production.

• Undertake large-scale hybrid rice seed production in order to produce adequate amounts of hybrid seeds for use by farmers in target areas.

• Realize 150 000 ha of F₁ hybrid cultivation area by 2002.

• Enhance the national capacity for hybrid rice development and use through research and development, training and technology promotion programmes.

• Commercialize the use of hybrid rice technology in order to increase national rice production, enhance farmer productivity and competitiveness, and attain rice self-sufficiency.

STRATEGIES

• Utilization of PSB Rc72H (Mestizo) in the hybrid rice programme in the short term and newly-released or adapted introductions in the long term.

• Involvement of IRRI, UPLB and PhilRice in the production of nucleus and breeder seeds of the parental lines of Mestizo hybrid.

• Deputization of private seed companies, such as the Jiangxi Academy of Agricultural Sciences (JAAS), Hybrid Rice Seed Enterprises (a division of SL Agritech Corporation) and Aventis CropScience, and other organized groups in the production of foundation seeds of Mestizo hybrid in addition to activities led by PhilRice.

• Involvement of the private sector (seed companies, organized hybrid rice seed growers with compact seed production areas) in hybrid rice seed production.

• Organization of a hybrid rice seed industry involving both the public and the private sector to produce, process and distribute hybrid seeds throughout the country.

• Government procurement of parental lines and hybrid seeds.

• Importation of seeds of adapted rice hybrids as a stop-gap measure while the capacity for hybrid rice seed production is enhanced.

• Enhancement of the technical capacity of the public sector to undertake efficient and high quality parental line and hybrid seed production through demonstrations and hands-on training and packaging of these technologies.

• Development of the technical capacity for hybrid rice cultivation using Farmers' Field Schools.

• Promotion of hybrid rice seed production for organized seed growers with compact areas to ensure sufficient local supply of hybrid seeds.

• Promotion of the use of hybrid rice by farmers through demonstrations and a tri-media campaign.

• Continued and strengthened hybrid rice research and development efforts to generate improved technologies.

• Involvement of local government units (LGU) in target areas in the programme, particularly in capacity building and technology promotion.

• Tapping of the national rice research and development network, the Department of Agriculture (DA) regional funded universities (RFU), bureaus and attached agencies and LGUs for assistance in programme implementation.

• Tapping of government financing institutions for the necessary capital by hybrid rice cultivators and seed producers.

• "Compact farming" strategy adopted for F₁ hybrid rice cultivation.

• Linkages with Chinese and other hybrid rice institutions forged and supported to enhance the national capacity for hybrid rice development and use.

• Government enactment of policies and standards to make hybrid rice cultivation and seed production attractive, profitable and sustainable

TARGETS

Hybrid rice technology is to be expanded in the following target areas (either for hybrid rice seed production or for cultivation):

First priority provinces:

• Cagayan, Isabella, Nueva Ecija, Pangasinan, Mindoro Oriental, Mindoro Occidental, Davao del Sur, Davao del Norte, Davao Oriental

Second priority provinces:

• Ilocos Norte, Nueva Viscaya, Quirino, Ifugao, Leyte, Bukidnon, Misamis Occidental South Cotabato, Maguindanao, Cotabato, Sultan Kudarat, Agustan del Sur

Hybrid rice cultivation areas must have highly productive, favourable, irrigated rice-growing environments, and the F₁ hybrid rice cultivation area is set to reach 150 000 ha by 2002. There are four AxB training courses for selected public sector personnel. Target seed production areas must have optimum conditions for hybrid rice seed production and trained and experienced personnel:

• Training courses on hybrid rice seed production for organized seed growers in potential hybrid seed production areas.

• Technology promotion activities (demonstrations, field days, workshops, mass media campaign) in hybrid rice cultivation areas.

• Adaptive research, particularly in target seed production and cultivation areas.

• Seed importation and distribution mechanisms to cover the initial stages of the programme.

ACTIVITIES

The activities to be undertaken during the next two years include: parental line seed production, involving nucleus, breeder and foundation seed production (Table 4); hybrid seed production by seed growers and companies; hybrid rice cultivation by farmers on a commercial scale; technology demonstration; training; information campaign; research and technology development; and policy formulation and advocacy (Table 5).

EXPECTED OUTPUTS

Immediate

• Production of parental and hybrid rice seeds in sufficient quantities for large-scale commercialization of hybrid rice technology in selected areas of the country.

• Attaining the highest level of genetic and physical purity in parental line seeds, thereby increasing AxR seed production yields while reducing labour costs in AxR seed production.

• Planting of 150 000 ha of hybrid rice by 2002 in the Philippines.

• On-farm demonstration and realization of the potential of hybrid rice technology to increase national rice production.

• Training of over 1 000 farmers, seed growers, seed inspectors and researchers in hybrid rice technology.

• Generation of improved technologies for hybrid rice cultivation and seed production.

• Generation of interest in the use of modern technologies to help the country attain national food security.

Medium and long term

• Development of a new, competitiveness-enhancing and higher-yielding technology for Filipino farmers.

• Establishment of a national hybrid rice seed industry with participation of both the public and the private sector.

• Training of Filipino farmers, seed growers and seed inspectors in parental line and hybrid rice seed production and cultivation.

• Large-scale demonstration of hybrid rice technology nationwide, generating full awareness of the technology's potential.

• Development of better hybrids, followed by generation, on-farm validation and packaging of technology packages for hybrid rice cultivation.

• Creation of farmer demand for F₁ hybrids, leading to long-term sustainability of the technology.

• Creation of more jobs in the seed industry sector due to labour-intensive operations.

• Increase in national rice production and agricultural productivity.

• Enhancement of competitiveness of Filipino farmers under the global economic order.

TABLE 4

Seed production targets for various seed classes of parental line seed necessary to plant 150 000 ha to hybrid rice by 2002 and beyond

TABLE 5

Project activities and implementing institutions or sectors involved, 2001-02

Note:

UPLB = University of the Philippines in Los Baños.
JAAS = Jiangxi Academy of Agricultural Sciences.
DA = Department of Agriculture.
GFI = Government Financial Institutions.
LGU = Local Government Unit.
RFU = Regional Funded University.

BUDGETARY REQUIREMENT

The estimated budget for project implementation during 2001 is summarized in Table 6. The budget is mostly for the procurement of A line (female parent) and hybrid seeds and includes:

• maintenance and operation costs for PhilRice-implemented AxB and AxR hybrid seed production;

• training of farmers, seed growers, seed inspectors, researchers and extension personnel;

• technology demonstration for AxB and F₁ seed production and cultivation;

• information campaign; and

• research and development activities in breeding, nutrient and agronomic management, pest management, socio-economics, engineering and mechanization and seed production; and development of location-specific hybrid rice technologies.

TABLE 6

Budgetary requirement for project implementation during 2001 (million pesos)

The private sector is expected to fully finance seed production activities while the Government must guarantee the market.

Also included in the budget are: capital outlays for specialized processing equipment for hybrid and parental line seeds, training equipment, greenhouse equipment for nucleus seed production, laboratory equipment for hybrid rice breeding, hybrid testing and certification and other research and development activities; and an allocation for the construction and maintenance of storage facilities.

A new hybrid rice laboratory is currently being constructed in Maligaya to serve as a centre for hybrid rice research and development activities in the country. Equipment, however, needs to be purchased to make the laboratory fully functional once completed.

The construction of screenhouses is particularly important to ensure the highest purity in parental and hybrid seeds. Impurities may cause the non-attainment of the true potential of hybrid rice varieties that has been shown to be between 15 and 25 percent higher than that of conventional varieties.

REFERENCES

Redoña, E.D., Malabanan, F.M, Javier, L.J., Yabes, S.I., Ordonez, S.A. & Obien, S.R. 2001. Exploitating rice heterosis in the Philippines in rice research for food security and poverty alleviation. In Proceedings of the International Rice Research Conference, Los Baños, Philippines, 31 March-3 April 2000. p. 193-203. Los Baños, Philippines, IRRI.

Status, progress, policies and expectations for the hybrid rice research and development programme in Sri Lanka - Shelton Wijenayaka Abeysekera,^a Demuni Sumith de Zoysa Abeysiriwardena^b and Dharmasiri Bope Weeratunge^c

^a Research Officer and
^b Director, Rice Research and Development Institute, Batalagoda, Sri Lanka
^c Director, Seeds and Planting Materials Development Center of Agriculture, Peradeniya, Sri Lanka

INTRODUCTION

Rice sector

Sri Lanka is an island in the Indian Ocean within the equatorial belt lying from 5°55' to 9°50' North and from 79°42' to 81°52' East with an area of approximately 6.56 million hectares (Mha). It measures 435 km north to south and 255 km east to west. Three distinct physiographic regions can be identified within the island: a lowland peneplain ranging from sea level to 305 m above sea level, a middle peneplain (915 m asl) and an upland peneplain (over 2 440 m asl).

In Sri Lanka, there are three rice production systems, which differ according to the water management approach: major irrigation, minor irrigation and rainfed. Each system varies depending on the water resources available, the method of supply to the crop and the water management techniques adopted. The major and minor schemes cover irrigated rice with a totally or partially controlled water regime, while rainfed to a large extent depends on direct precipitation with or without water conservation methods (i.e. bunding). Most of the rice lands are inland valleys but there is also a limited area in the coastal plains and minor flood plains (Table 1).

TABLE 1

Classification of rice lands based on source of water

The country is divided into eight agroclimatic regions on the basis of elevation, temperature and rainfall. There are three major climatic zones based on rainfall. The dry zone (rainfall 900-1 500 mm) constitutes about 41 percent of the rice area. Agriculture in this zone depends on the "tank" system and major irrigation schemes as well as on limited rainfed farming. The intermediate zone (1 500-2 200 mm) and wet zone (2 200-5 000 mm) constitute 23 and 36 percent, respectively, of the total rice area. They depend on rainfed farming and supplementary irrigation.

Importance of rice

Rice is the staple food of Sri Lanka and the most important crop in the country. In the past the main aim of the agricultural sector was to achieve self-sufficiency in rice (Oryza sativa L.). Until the mid-1950s, Sri Lanka had a strong export market for tea which was sold at high prices. The balance of payments was positive and much of the food needed by the population was imported. This was the case for rice, the staple food, as well as for subsidiary food crops. With the decline in tea prices and negative payments in terms of trade, the Government focused its attention on achieving self-sufficiency in food, especially rice.

Rice represents the livelihood for more than 1.8 million farm families in Sri Lanka. More than 30 percent of the total labour force is directly involved in rice or rice-related activities. Per caput consumption is about 100 kg per year and the annual cultivated rice land area is about 830 000 ha, but further expansion of the national rice area is not possible. Sri Lanka must therefore raise its present yield level of 3.7 t/ha to 4.5 t/ha by 2005 in order to achieve self-sufficiency in rice.

Rice production

In Sri Lanka, one-quarter of the total land area (1.64 Mha) is under agricultural crops: rice, tea, rubber and coconut. Rice occupies 0.73 Mha of the total cultivated area. With two cropping seasons - major (maha) and minor (yala) - the annual cropping area for rice is about 0.87 Mha.

The annual rough rice production in Sri Lanka is about 2.8 million tonnes (Mt) with an average yield of 3.7 t/ha. The average yield of major and minor irrigated and rainfed land in the minor season is 4.3, 3.4 and 2.7 t/ha, respectively, while in the major season it is 4.2, 3.7 and 3.0 t/ha. If the current consumption rate remains unaltered, Sri Lanka will require about 3.9 Mt of rough rice to feed its population of 20 million in 2005. To achieve this target, Sri Lanka must raise the yield from 3.7 to 4.5 t/ha by 2005.

Problems of the rice sector

The main problem currently facing the rice sector in Sri Lanka is low and stagnating yield, despite the adoption of semi-dwarf high-yielding cultivars. Since further expansion of the rice area is not possible, the alternative is to increase productivity per unit area of land with the adoption of the appropriate technology at farmer level.

Efforts should be made to improve seed paddy quality and soil fertility status, and to adopt better crop management techniques in order to raise the rice yields obtained with the existing cultivars. Furthermore, efforts are being made to exploit new plant type and hybrid rice technology for the improvement of varietal yield potential.

HYBRID RICE IN SRI LANKA

The only way to increase rice production while keeping rice cultivation economically viable is to increase yield per unit area at little or no additional cost. To this end, hybrid rice technology has been identified as a potential solution. Sri Lanka re-initiated its hybrid rice research and development programme in 1994, in collaboration with the International Rice Research Institute (IRRI), at the Rice Research and Development Institute (RRDI) of the Department of Agriculture. Since 1997 the programme has been financially supported by the IRRI-ADB (Asian Development Bank) project on the development and use of hybrid rice in Asia. Phase 1 of the project has produced remarkable results in hybrid rice research and development in Sri Lanka.

Hybrid rice research and development programme

Sri Lanka initiated the hybrid rice research programme at the Central Rice Breeding Station (now RRDI) in the early 1980s for the development of hybrid rice suitable for local conditions. For two years, hybrid rice research had low priority and little or no progress was made - mainly due to the lack of adaptable genetic materials and insufficient resource inputs. Thus, the hybrid rice research programme was suspended until the real need for hybrid rice was felt.

In the early 1990s, there was rice yield stagnation in the country, despite the continuous development of new inbred lines. An open economy and the involvement of the private sector in the seed production process was encouraged. Highly adaptable genetic materials and improved technologies for the development of hybrid rice in the tropics (produced by IRRI) were available. Thus, the hybrid rice research and development programme was relaunched and given high priority in Sri Lanka.

After 1994, the Ministry of Agriculture promoted the introduction of hybrid rice technology in Sri Lanka in consultation with the Department of Agriculture. The Minister of Agriculture invited China to help strengthen the hybrid rice research and development programme in Sri Lanka. A team of Chinese scientists visited Sri Lanka in 1996, but came to the conclusion that the direct introduction of Chinese hybrid rice to Sri Lanka would be ineffective. Sri Lanka therefore had to develop its own hybrids using introduced and local germplasm. However, the research programme begun by China (1996-99) to develop hybrid rice locally was not successful. The genetic material introduced from China could not be maintained without its continuous introduction.

Hybrid rice research and development continues at RRDI and is given high priority.

Objectives and progress

• Evaluation of promising genetic material from IRRI and other countries for adaptability in the target environments.

• Identification of introduced cytoplasmic male sterile (CMS) lines suitable for Sri Lanka and transfer of the CMS characteristic to promising Sri Lankan lines.

• Development of hybrid rice combinations (F₁) in Sri Lanka using adaptable CMS lines, and evaluation of their performance in target environments.

• Development of a locally adapted management package for hybrid rice seed production.

• Development of appropriate agronomic practices for hybrid rice cultivation.

• Increased awareness of hybrid rice technology and its availability to interested farmers.

Development and introduction of promising hybrid rice

To develop and introduce promising hybrid rice, priority should be given to: identification of promising parental lines adaptable to Sri Lankan conditions; evaluation of hybrids in multilocational trials in research fields; and on-farm evaluation of promising hybrids. Sri Lanka has to date made remarkable progress in these areas under phase 1 of the project.

Identification of promising parental lines

• One CMS line (PMS 11A) from India and six CMS lines (IR58025A, IR68281A, IR68887A, IR69623A, IR69625A and IR68889A) from IRRI have been identified as adaptable and stable under local conditions. All these lines are improved plant type.

• Some well-adapted local varieties and lines were identified as maintainers or good restorers for the CMS lines, e.g. H4, At 95-6-8, Bg 95-328, Bg 97-3272, Bg 98-757, Bg 95-425, Bg 95-905, Bg 98-601 and Bg 98-919.

• A local CMS line (Bg CMS 1A/B) has already been developed at RRDI by transferring the CMS characteristic from locally adapted PMS 11 to local variety Ld 355 with small round (Samba) grain in the three and a half month maturity group.

Evaluation of hybrids in multilocational trials in research fields

Following testing over two seasons (one maha and one yala) and two locations (target areas for hybrid rice production: Thalawa and Girandurukotte), two hybrid varieties were identified as promising and adaptable under Sri Lankan conditions: IR69676H and IR69690H, which involve locally adaptable CMS line, IR58025A, as the female parent. These two hybrids show consistently high standard heterosis (12-84%) over locations and seasons. Three locally developed hybrids, namely Bg HR1 (IR69616A/H4), Bg HR12 (IR58025A/BR 827-35-2-1-11R) and Bg HR6 (PMS 11A/IR54742-22-19-3R), have consistently shown a high level of standard heterosis (31-45%) in yield tests conducted in two locations (Batalagoda and Girandurukotte) in the target region. Bg HR1 has also shown a high level of standard heterosis (45%) at Mahailluppallama in yala 2000. However, the CMS line (IR69616A) used to develop Bg HR1 showed only 97 to 98 percent pollen sterility, whereas the CMS line (IR58025A) used to develop two other hybrids has consistently shown 100 percent sterility over seasons under local conditions. These three promising hybrids will be further tested for standard heterosis in the target region. Bg HR1 and Bg HR6 were found to be superior to standard inbreds in terms of grain quality.

On-farm evaluation of promising hybrids

Since the evaluation of hybrids in multilocational trials in research fields is not yet completed, no promising hybrids are yet available for on-farm evaluation.

Development of a locally adapted management package for hybrid rice seed production

Small-scale seed production is necessary to provide seed for yield trials. Using the isolation-free method, a seed yield of between 0.75 and 0.87 t/ha can be produced the first time in seed production plots at RRDI.

Large-scale seed production (plot size 100 m²) was experimented in the target area using the hybrid combinations: PMS11A/H4, PMS11A/IR54742-22-19-3R, IR58025A/BR827-35-2-1-1-1R, IR62829A/IR33509-26-02-2-2R and IR69616A/H4. A seed yield of 0.22 to 1.4 t/ha was obtained with the strict isolation method. Further studies are needed to improve hybrid rice seed production in Sri Lanka.

Development of appropriate agronomic practices for hybrid rice cultivation

Nitrogen response studies were conducted with one of the promising hybrids (Bg HR1). At all levels of N (0, 100 and 150 kg/ha), Bg HR1 performed better than inbred checks, indicating high N-use efficiency in hybrids. The N response of hybrids was found to be higher than inbred checks, indicating that hybrid yield can be improved by increasing N application. However, further studies are needed to optimize hybrid rice in Sri Lanka.

Awareness of hybrid rice technology

Several informal meetings, training courses and technical briefings were conducted for officials from different public and private sector organizations. A national Workshop on Hybrid Rice Network for Sri Lanka was held on 26 June 2000 with the patronage of the Minister of Agriculture. A hybrid rice network for Sri Lanka has already been established with full political support.

Constraints and problems identified during phase 1 of the project

The main constraints and problems related to hybrid rice research and development emerged during phase 1 of the project and may be identified under two areas: technical and institutional.

Technical

• Inadequacy of promising CMS lines with grain types preferred by consumers. Transferring CMS characters to local varieties identified as potential maintainers may help overcome this problem.

• Limited grain yield heterosis in experimental hybrids. One of the reasons for this may be the low level of genetic diversity between the small number of CMS lines identified as adaptable under local conditions. Another reason may be the narrow genetic base of the locally available varieties that can be used as restorers.

• In Sri Lanka, direct seeding is practised on 85 percent of the rice land area, and promotion of transplanting with hybrid rice is therefore difficult.

• High cost of GA₃ in Sri Lanka. Since GA₃ is not locally produced, Sri Lanka should find ways and means to import it at a low price. Alternatively, technology should be generated to produce hybrid rice seed without application of GA₃.

Institutional

• Inadequacy of resource personnel. This was recently solved by allocating an additional two permanent research officers and one permanent research assistant for hybrid rice research. However, shortage of skilled labour is still a problem.

• Inadequacy of infrastructure and transport facilities. A separate small laboratory unit within RRDI is necessary for an efficient and effective hybrid rice research and development programme. Conducting on-farm trials is extremely difficult without adequate transport facilities.

• Inadequacy of land area available. The allocation of additional land is under consideration.

• Lack of facilities to produce the required quantities of hybrid rice seed in government seed farms.

Proposed activities for the hybrid rice programme

Technology generation

• Selection or breeding of locally adapted rice hybrids with acceptable grain quality and adoption of associated seed production technology using breeding material from IRRI, China and India.

• Development of agronomic and nutrient management practices for maximizing yields from the elite rice hybrids.

• Experiments to study the prospects and problems of introducing hybrid rice with direct-seeding under the problem soil conditions of Sri Lanka.

Seed production

• Testing the available seed production technology in prospective seed production areas in collaboration with seed production agencies in Sri Lanka.

• Production of breeder and foundation seed of the parental lines of released rice hybrids on a sustainable basis in collaboration with seed production agencies.

• Production of certified and/or truthfully labelled seed of commercial rice hybrids with the help of public, private and NGO seed production agencies.

• Training courses on hybrid rice seed production for prospective seed production agencies in Sri Lanka utilizing resource personnel from China, India and IRRI.

Technology transfer

• On-farm and front-line demonstration trials of suitable rice hybrids in selected target areas of Sri Lanka.

• Development of deployment strategies and public awareness materials to promote the use of hybrid rice technology.

• Training courses on hybrid rice cultivation for extension officers and farmers.

• Government support for the promotion of hybrid rice technology and the hybrid rice seed industry in the first five years of the commercialization of the technology.

Impact

• Increased rice yields and production under the irrigated transplanted conditions of Sri Lanka.

• Increased seed industry activities in public, private and NGO sectors.

• Increased rural employment opportunities through the seed industry.

Beneficiaries

• Rice farmers, who will obtain higher yield and incomes by cultivating hybrid rices and higher incomes by producing hybrid seeds.

• Rice consumers, who will continue to buy rice at affordable prices.

• The country, which will save foreign exchange thanks to the reduction in rice imports.

• Agricultural labourers, who will have greater employment opportunities in the hybrid rice seed industries.

• Seed production agencies in public, private and NGO sectors, which may increase commercial activities in rice seed.

• Researchers and research institutions, which will have the opportunity for close collaboration with IRRI, China and other countries working on hybrid rice.

Risks

Hybrid rice cultivation may not be sufficiently economically attractive for large-scale adoption by rice farmers if market prices decrease due to higher yields or if equally high-yielding inbred rice cultivars become available.

Assumptions

• The human resources and infrastructural facilities required for technology generation, seed production and technology transfer will be provided.

• Participating institutions and agencies will work in a coordinated manner.

• Appropriate deployment strategies will be adopted for hybrid rice cultivation and hybrid seed production in the country.

• There will be no unforeseen major problem in hybrid rice cultivation or hybrid seed production in the country.

Seed paddy production

The Department of Agriculture (DOA), as the institute responsible for the rice varietal improvement programme, has the infrastructure facilities to satisfy only 5 to 6 percent of the total seed paddy requirement of improved rice cultivars in the country. The DOA therefore relies heavily on farmer-to-farmer lateral spread of pure seed paddy. It is necessary to expand quality seed paddy production and distribution, for which the active participation of the private sector is expected, particularly in the field of hybrid rice seed production.

POLICY ASPECTS OF SEED AND PLANTING MATERIAL OF SRI LANKA^[2]

Background

The seed industry in Sri Lanka is rapidly maturing into a dynamic and effective force, bringing the best and most adapted varieties of crops and horticultural plants to farmers and home gardeners in Sri Lanka.

In the late 1950s, the DOA set up an organized seed production programme, developing high-yielding varieties through breeding and selection. Until recently, it was the responsibility of the DOA to distribute the seed of about 70 varieties of more than 20 crops. Additionally, the grafts and seedlings of a wide array of horticultural crops are produced and distributed by the DOA.

Purpose

Guidelines are needed to encourage private sector participation in the production of quality seed, in order that the basic seed requirement may be met (thanks also to the efforts of the DOA). In the long run, viable seed industries should be established. The aim is to help Sri Lankan farmers gain access to high quality seed - either from domestic sources or through importation - and increase yields, production and farm income. The policy focuses on the formation and establishment of seed enterprises to produce and market the seed. Government agencies, including the DOA, will play a more active role in providing support and ensuring high quality seed production and coordination.

New seed policy

The seed and planting material policy comprises the following components:

• variety development and release;

• provision of basic seed and planting material;

• commercial seed production, processing, marketing and utilization;

• importation of quality seed and planting material;

• coordination and development assistance;

• certification and quality promotion; and

• other support activities.

Variety development and release

• The Ministry of Agriculture (MOA) will invite seed and planting material entrepreneurs to be members of the National Seed and Planting Material Committee, which has the mandate for decision-making in the general seed programme, variety release, and seed and planting material standards. Through this process, the technical capacities of the public sector research agencies may be optimized.

• The MOA will share the manpower, facilities and other resources with the private sector. Detailed procedures mutually acceptable to the Government and the private sector will be worked out.

• The DOA will make basic genetic material and locally developed advance lines available to public and private sector organizations interested in breeding or testing such material.

• The MOA will encourage the enactment of breeders' rights as an incentive to plant breeders over the next three years.

• Variety development organizations will continue to maintain the purity of their respective varieties.

• Testing and release of new local varieties developed by the public and private sectors and requiring official certification will be carried out by the DOA in a timely manner.

Provision of basic seed and planting material

• The DOA will provide adequate quantities of basic seed of the recommended varieties to private seed enterprises at negotiated prices.

• The certified seed production and distribution programme of the DOA will be gradually phased out. In the medium term, the DOA will focus on the provision of basic seed. When independent seed enterprises mature and are capable of producing basic seed, the production of this class of seed by the DOA will be reduced correspondingly.

• Information about promising cultivated varieties will be made available to growers.

• Limited quantities of plants of varieties not yet tested and recommended will be made available to growers for testing in suitable regions. An "all care no responsibility" approach will be adopted in order that interested growers may try them.

Commercial seed production, processing, marketing and utilization

• The Government will not compete with the private sector in commercial seed production.

• Seed enterprises will be given assistance for commercial seed production. The concept of "seed enterprise" includes farmer organizations, cooperatives, agro-industrial firms, individual companies and NGOs. Assistance to be provided includes:

  - plant quarantine services;
  - basic seed when required;
  - technical assistance and training;
  - custom cleaning and storage services where possible;
  - market information;
  - internal quality control and certification; and
  - quality promotion.

• Tax concessions applicable to investments in agriculture will be made available to those in the seed industry.

• To ensure price stabilization, buffer stocks of selected crops will be maintained.

• No duties will be levied on machinery and equipment imported for seed production, processing and quality control.

Importation of quality seed and planting material

• The private sector will continue to import seed and planting material so as not to hold back the seed industry.

• All seeds and planting material imports should be subject to plant quarantine and quality control.

• Rice and allied plants (Oryza L.): Where any plant or plants of the genus Oryza L. are imported into Sri Lanka, under regulation 35 the Director-General may permit such importation only under the following conditions:

  - Only the Director of RRDI (or authorized representative) may carry out the importation.

  - Only seeds may be imported.

  - Each consignment must be accompanied by a copy of the Plant Importation Permit issued by the Director-General and all other necessary certificates and official statements; it must be addressed to the Director-General.

  - At the port of entry, an authorized officer inspects the consignment and directs it to the National Plant Quarantine Station.

  - At the National Plant Quarantine Station, the consignment is disinfected in an approved manner and the containers and all packing materials imported are destroyed.

  - The authority to release imported material from the National Plant Quarantine Station rests with the Officer-in-Charge, who only releases the imported material once satisfied with the phytosanitary conditions of the consignment.

  - The imported seeds are grown under post-entry quarantine conditions in a location approved by the Director-General for a period specified by the Director-General.

Seed certification and quality promotion

• An intensive programme for the use of quality seeds will be undertaken.

• Official certification will be essential for seed and planting material produced and offered for sale as certified or quality assured seed. All seeds marketed must meet the minimum standards prescribed by the Seed Certification Services of the DOA. A seed container labelling system will be implemented.

• All seeds imported or produced locally must be labelled according to the minimum standards to be laid down in the Seed Law. Until the Seed Law is actually passed, the standards established by the Seed Certification and Plant Quarantine Center of the DOA apply.

THE RESEARCH PLAN AND MILESTONES

• Continuation of hybrid rice research and development activities.

• Formation of a national hybrid rice network for Sri Lanka by 2000.

• Training on hybrid rice technology by 2000.

• Identification of the first promising hybrid rice variety by 2002.

• Development of seed production techniques and package of agronomic practices by 2002 for hybrid rice cultivars.

• Extensive testing of hybrid combinations in farmers' fields for adaptability; recommendation of the first hybrid variety by 2002.

• Initiation of basic seed production (nucleus seed, breeder seed, foundation seed) by 2002.

• Initiation of commercial seed production in 2003 and subsequent release of seed paddy for farmers in 2004.

CONCLUSION

The hybrid rice research and development programme in Sri Lanka will be continued and expanded according to the need for increased rice production and on the basis of the progress made in hybrid rice research over the past few years. A programme of activities for hybrid rice research and development in the next three years has already been prepared, on the assumption that the problems and constraints identified will not limit future progress. Sri Lanka's seed policy does not permit the importation of rough rice except for research purposes, to avoid the seed supply of the staple food becoming dependent on foreign sources for food security reasons.

Policy support for hybrid rice in Viet Nam - Ngo The Dan

Vice Minister of Agriculture and Rural Development, Hanoi, Viet Nam

During the last decade, the implementation of agricultural policies has been considered a "priority front" and "foundation" for the nation's industrialization and modernization. Agricultural production (including agriculture, forestry and aquaculture) in Viet Nam has made significant progress. The annual growth rate of agriculture is 4.5 percent. The greatest achievements to date are attaining self-sufficiency in agriculture and ensuring national food security, while increasing the commodity rate and ranking high at regional and world level. Viet Nam is one of the most important exporting countries for four agricultural commodities: rice, coffee, cashew and pepper. The annual growth rate of food production is 5.2 percent per year and production has increased by 1 million tonnes (Mt) over the last year. At present, average per caput food consumption is 450 kg/year. Viet Nam meets the standards of national food security.

However, Viet Nam continues to pay considerable attention to the research and development of hybrid rice for the following reasons:

• In the process of industrialization and modernization, the population of Viet Nam is growing while agricultural land is decreasing. Therefore, increasing food production and yield is still an essential factor for guaranteeing national food security. Hybrid rice may solve the above conflict as all hybrid rice season crops in the various ecologies achieve yields 1.0 to 1.5 t/ha higher than conventional rice.

• Viet Nam has achieved national food security and has surplus food to export; but in some regions, food production does not meet domestic demands, especially in remote and mountainous areas where the rural infrastructure is undeveloped and transportation still meets a lot of difficulties. Under such conditions, the application of hybrid rice technology has advantages and is welcomed by farmers. Hybrid rice makes an important contribution to hunger alleviation and poverty elimination in rural areas.

• In order to develop diversified export-oriented commodity agriculture, Viet Nam is adjusting the agricultural structure to make full use of the comparative advantages in each region, reducing the rice area to make way for other farm products of high economic value and with available markets (e.g. vegetables, fruit crops, cash crops, forestry and fishery). Hybrid rice development with high productivity is the solution for satisfying food demand.

Over the last nine years - since farmers living in the border region began to successfully cultivate Chinese hybrid rice varieties - the Ministry of Agriculture and Rural Development (MARD) has promoted research and development of hybrid rice in Viet Nam with positive results. No other technology matches the success of hybrid rice in terms of propagation and support from farmers.

So far, the hybrid rice cultivated area has increased to 340 000 ha from 100 ha in 1991. Viet Nam has the technical competence to produce F₁ hybrid rice seeds and is able to meet domestic demand. Viet Nam should be self-sufficient in F₁ hybrid seeds by 2005.

MARD in particular and the Government of Viet Nam in general have adopted numerous policies supporting research in hybrid technology and promoting agricultural extension to guide the farmers in production, including guidance in the execution of the two projects, TCP/FAO/VIE 2251 and 6614, supported by FAO within the framework of cooperation between Viet Nam and FAO. These projects are considered a premise for research and development of hybrid rice in Viet Nam. Experts from FAO and IRRI have provided much useful knowledge to local staff to support their sustainable professional activities.

The Government (and MARD as the agency directly responsible) has provided resources to support the following research and development activities:

• Formulation of the hybrid rice programme for submission to the Government for approval as a basis for investment and development.

• Establishment of the Hybrid Rice Research Centre under the administration of the Viet Nam Agricultural Sciences Institute for assuming research on the conservation of pure-lines from introduced hybrid combinations. Current seed production technologies have been deployed and new Vietnamese hybrid rice combinations created. In the last five years, the annual investment in research was on average US$0.5 million.

• Production of F₁ hybrid seeds and hybrid rice on a large scale in four focal point provinces where farmers are competent in the new technology and where the administration supports investment and development. F₁ hybrid seeds are usually produced by progressive farmer households with support from the Agriculture and Forestry Extension Department of MARD and the Department of Agriculture and Rural Development of the provincial government. The Government provides free parental lines, fertilizers, insecticides and growth regulating agents, to a total cost of US$400/ha. In remote and mountainous low-income areas, F₁ hybrid seeds are provided free for production on a large scale. Thanks to the extension of hybrid rice application in mountainous areas, the area of upland rice has been reduced. On average, when 1 ha of hybrid rice is grown, 1 ha of forest will be saved from fire to clean up land for cultivation. The state-owned enterprises producing F₁ hybrid lines receive assistance from the Agriculture and Rural Development Department.

• Credit policy: growing hybrid rice will raise the production cost by 5 percent compared to inbred rice cultivation, and farmer households investing in F₁ hybrid seed production will have to increase the production costs two- or threefold (i.e. almost US$1 500/ha - 20-22 million dongs/ha). The demand for credit is therefore very high and interest rates are 0.5 to 0.7 percent per month.

Policies, at national and local level, in favour of large-scale adoption of hybrid rice have benefited farmers. The Government will continue to invest in research and development of hybrid rice and to support farmers in the adoption of new technologies, with the aim of reaching the production target of nearly 1 million ha of hybrid rice cultivated with self-produced hybrid seeds by 2010.

Viet Nam has only modest experience in research and development of hybrid rice. Viet Nam must increase efforts and seek further cooperation and assistance from China, India, IRRI and other countries with extensive experience in hybrid rice.

Hybrid rice production in Viet Nam - Quach Ngoc An

Deputy Director, Department of Agricultural and Forestry Extension, Hanoi, Viet Nam

BACKGROUND

Viet Nam is located in Southeast Asia. It borders in the north with China, in the west with Laos and Cambodia, and in the east with the South China Sea. Viet Nam has a population of about 75 million, of which 65 million live in rural areas. The total area of the country is approximately 330 000 km². The total land potential for agriculture is 11.5 million hectares (Mha). The country is divided into eight major agro-ecological zones, on the basis of soil, topography, climate and agricultural land-use patterns.

At present about 7.3 Mha are cultivated as follows:

Viet Nam is an agricultural country based on rice production. Agricultural production in Viet Nam has developed rapidly and has contributed to raising the living standards of people in general and farmers in particular. It also creates favourable conditions for the promotion of other economic sectors.

The average growth rate of food production in five-year plans has been as follows:

1986-1990: 3.38%
1991-1995: 4.93%
1996-2000: 4.28%

FIGURE 1 Agricultural land-use in Viet Nam

The average rice yield has also increased:

1986-1990: 2.98 t/ha
1991-1995: 3.43 t/ha
1996-2000: 4.00 t/ha

The average food output was 274 kg per caput per year in 1976, and it is now over 400 kg per caput per year. Once a food-deficient country, Viet Nam has become food self-sufficient. In 1989, it began exporting rice and is now ranked the second biggest rice exporter in the world after Thailand. The average volume of rice exports in 1989-1990, 1991-95 and 1996-2000 was 1.5, 1.72 and 3.6 million tonnes (Mt), respectively.

However, food production varies according to the agro-ecological zone, natural calamities occur, about 15 percent of farmer households have a low income and land resources must be shifted to higher-value crop cultivation. National food security therefore remains a high priority. Further development of hybrid rice production is to focus on increasing yield and production.

TABLE 1

Rice production, 1990-2000

HYBRID RICE DEVELOPMENT IN VIET NAM

The Deputy Prime Minister, Nguyen Cong Tan, when at the Ministry of Agriculture and Rural Development (MARD), adopted specific policies to keep pace with advanced hybrid rice technology and to facilitate its immediate adoption in agricultural production in Viet Nam. The Department of Agricultural and Forestry Extension (DAFE) benefited from two projects (TCP/FAO/VIE 2251 and TCP/FAO/VIE 6614) and received assistance from IRRI and international friends with the aim of transferring technology to farmers and developing commercial hybrid rice and F₁ seed production.

The performance of hybrid rice production

The first model of hybrid rice production was located in the Phu Lap cooperative, Phu Xuyen District, Ha Tay Province under an area of 55.3 ha. Following 10 years of development, hybrid rice has produced the following results:

• The total area of hybrid rice reached 1 265 865 ha between 1991 and 2000. The increase has been particularly rapid in the last five years:

• The total production in 10 years of development is 7 979 437 tonnes. Use of heterosis gave an increase of 1 835 504 tonnes (23% higher than with pure-line varieties).

• The average yield of hybrid rice in the last 10 years is 6.30 t/ha. The daily yield of hybrid rice areas can be seen in Table 2.

• The hybrid rice area has expanded, especially in the spring crop. In some provinces, hybrid rice occupies a high proportion of the total area of cultivated rice:

The number of provinces cultivating hybrid rice varies according to the agro-ecological zone (Table 3).

The performance of F₁ seed production

There is a high demand for seed to produce commercial hybrid rice, and F₁ seed production in Viet Nam only satisfies 13 percent of demand due to:

• natural calamities which cause production risks;

• shortage of qualified technicians to provide training and guidance to farmers; and

• lack of investment in production.

The production of F₁ hybrid rice seed in Viet Nam is to be implemented as follows:

1. The principal source is initially imported seed; domestic seed production is supplementary.

2. Domestic seed production is to be gradually promoted to bring it in line with the imported volume.

3. The principal source will eventually become domestic production and imports will be merely supplementary.

TABLE 2

Yield per day of hybrid rice in different localities

TABLE 3

Provinces cultivating hybrid rice in different agro-ecological zones

In F₁ hybrid rice production, the priority is to produce different combinations of widespread hybrid rice varieties and to obtain sufficient primary materials. It will then be possible to proceed to the selection of hybrid rice combinations with high yield potential and quality characteristics which reach market requirements.

Production of F₁ hybrid rice involves contracting with farmers and guaranteeing 100 percent consumption of the product; three economic sectors are concerned:

• the central seed company and provincial seed companies;

• private seed companies; and

• agricultural cooperatives assisted by government technicians and supported financially in part by the Government; seed produced will satisfy internal demand and the surplus will be sold to local seed companies or exchanged with other cooperatives.

MARD designated DAFE to be responsible for presiding over the hybrid rice programme. DAFE also provided guidance and information to farmer households participating in seed production. DAFE's role included:

• Management of two technical cooperation projects (TCP) funded by FAO and of technical assistance from international organizations for technology transfer to farmers.

• Acting as standing office for the national hybrid rice programme to coordinate all activities among research institutes, universities and local agencies participating in the national hybrid rice programme.

• Implementation of the technical itinerary concerning maintenance of parent lines, F₁ seed production and the intensive farming of commercial hybrid rice.

• Training farmers in seed production. During the last 10 years, there have been 146 000 farmer households taking part in seed production and 219 000 receiving on-farm technical training.

• Support to farmers in seed production through contracts between DAFE and provincial agricultural centres. To this end, over a 10-year period, the Government funded DAFE with 15 870 million dong (approx. US$1.1 million) from the national budget.

The Hybrid Rice Research Centre aims to purify parent lines for F₁ seed production sites and to release new combinations to farmers. In 2000, the national seed programme funded a hybrid rice seed project valued at 14 billion dong (approx. US$1 million) for execution by the Hybrid Rice Research Centre. The initial outcome of this project is 50 tonnes of A lines and 7 tonnes of R lines meeting the production standards set by the sector.

During the last 10 years, the agricultural extension network has provided guidance and assistance to farmers in the various provinces. The results are the following:

For F₁ hybrid rice seed production in agricultural cooperatives in Viet Nam, government support is necessary in order that farmers may take on the risks involved. Technology transfer to farmers through the agricultural extension network is the most economically effective approach. The production costs of hybrid rice seed in Viet Nam equal 60 percent of the import price. Hybrid rice seed produced locally is of good quality and gave high yields (7 - 9 t/ha) during tests in Yen Bai, Thanh Hoa and Nam Dinh provinces.

Farmers observed that: if F₁ seed yield goes below 1 t/ha, F₁ hybrid rice seed production produces a loss; from 1.0 to 1.5 t/ha, production breaks even; and seed yield of over 1.5 t/ha gives a clear profit.

Furthermore, qualified technicians and skilled farmers are required, and the technical itinerary must be strictly implemented.

EXPERIENCES IN HYBRID RICE DEVELOPMENT IN VIET NAM

Viet Nam's policy of keeping pace with advanced technology in hybrid rice and applying the technology to the specific conditions of the country has paid off.

Central Government and provincial authorities should provide specific guidance. A National Hybrid Rice Programme should be set up and led by a Vice-Minister of Agriculture and Rural Development to coordinate all activities of research, production and trading of hybrid rice. Development support policies are required, including:

• an investment policy for hybrid rice research institutions which would strengthen the hybrid rice research capacity;

• a price subsidy policy for farmers purchasing commercial seed:

  - 30% subsidy in the first three years for areas where production conditions are relatively favourable.

  - 50% subsidy for areas where production conditions are very difficult.

  - 100% subsidy for ethnic minorities living in high mountainous areas.

• a support policy aimed at sharing the farmers' risks; in order to encourage farmers to produce seed, the cooperative should provide an advance of production materials; the cooperative also purchases farmers' products at a price six to seven times higher than that of pure seed at the time of purchase;

• a tax reduction or exemption policy for agricultural taxes and irrigation fees, to be applied when farmers are faced with crop failure caused by natural calamity;

• a staff training policy: 600 scientists, technicians from research institutes and universities were trained, 70 of which overseas; almost 220 000 farmers received on-location training;

• a policy to encourage private companies to take part in hybrid rice production.

A system of hybrid rice production must be established with:

• more attention to scientific research on hybrid rice in order to create new hybrid rice combinations and supply pure seed for production;

• implementation by state and private seed companies of line multiplication and F₁ seed production; and

• organization by the extension system of the production of F₁ hybrid rice at farmer household level.

It is necessary to make use of assistance from UNDP, FAO, IRRI and organizations, individuals and international friends for the development of hybrid rice in Viet Nam.

CONCLUSION

Heterosis in rice production is a new achievement of the technology revolution in rice cultivation, capable of bringing about great changes in rice production in many countries of the world. Viet Nam has made significant advances in research and hybrid rice production and will continue to develop hybrid rice in the coming year.

Recent progress in hybrid rice research in Viet Nam - Nguyen Tri Hoan

Director, Hybrid Rice Research Centre, Hanoi, Viet Nam

NUCLEUS AND BREEDER SEED PRODUCTION

A major constraint in Viet Nam's hybrid rice programme is the lack of purified and multiplied parental seeds of rice hybrids. Nucleus and breeder seeds for parental lines were therefore identified with the support of the IRRI-ADB project. Attention focused on the parental lines of accepted and promising rice hybrids, and the results are presented in Table 1.

The yield advantage of F₁ hybrids using purified CMS and restorer lines can be seen in Table 2. On the basis of these data, the AMS 24-84 and restorer lines - Trac No. 4, Trac No. 5 for AMS 24A/Trac 64 and Que 46 for AMS24A/Que99 - were selected and multiplied for commercial hybrid rice seed production. Thanks to the constant supply of quality parental seeds, the F₁ seed production programme of Viet Nam has made rapid progress. F₁ seed production increased from 261 ha in 1997 to 1 300 ha in spring 2001. The quality of hybrid seeds is generally acceptable.

TABLE 1

Nucleus, breeder seed and foundation seed produced in Viet Nam, 1998-2000

Note: NS = nucleaus seed; Bs = breeder seed; FS = foundation seed.

TABLE 2

Yield evaluation of different pairs of parents of AMS24A/Trac64 (IR9761) and AMS24A/Que 99 in purification programme, 1998-2000

Note: CV (%) = 8.9; LSD 0.0 5 = 0.885; LSD 0.01 = 1.199.

TABLE 3

Duration of male sterility of TGMS under natural conditions in Hanoi (HRRC)

TABLE 4

Yield components and yield of seed production plot for six two-line hybrids

DEVELOPMENT OF TWO-LINE HYBRIDS

Exploitation of the climatic conditions

The average temperature range in Hanoi (1960-1980) from May to September is 27.4° to 29°C. This period would therefore seem suitable for F₁ seed production of two-line hybrids using TGMS (thermosensitive genic male sterile) as the female. However, the occurrence of three days in a row at 19.1°-23.5°C in May meant that spring in the Red River Delta was not actually suited to the production of F₁ seed of two-line hybrids based on the TGMS system. August, on the other hand, with no three continuous days below 26°C, is safe for TGMS, as the critical temperature to induce male sterility is [26°C for F₁ seed production. Flowering occurs in early September.

The period of complete male sterility of five TGMS lines was studied at the Hybrid Rice Research Centre (Table 3).

TGMS neared sterility from early May to 20 May, depending on the TGMS line. Complete sterility was reached on 5 September or 15 October. Consequently, F₁ seed production of two-line hybrids using TGMS as the female can be carried out in the summer. The female flowers in early September. The results of seed production in six hybrids are presented in Table 4.

TABLE 5

Result of TGMS multiplication at VASI, spring 1999

TABLE 6

Result of TGMS multiplication at Sapa (mountainous area), summer 1999 (seeding date May 23)

TGMS multiplication

Experiments to determine the sowing time for TGMS multiplication were carried out from 1996 to 1998 for TGMS7 and TGMS11. Results suggested that the optimum period for seeding TGMS lines is 10 to 25 December, with the crop flowering in April when the temperature reaches about 25°C and humidity and sunlight also increase. The yield of TGMS ranged from 1 876 to 3 657 kg/ha. The results of the multiplication of several TGMS lines in spring 1999 at the Vietnam Agricultural Sciences Institute (VASI) are given in Table 5. Yield ranged from 2 660 to 3 420 kg/ha, depending on the TGMS line.

TABLE 7

Some major characters of the promising TGMS lines in Viet Nam

In the 1998 winter/spring season, the natural temperature was above the critical sterility point (CSP) at the meiosis stage of the TGMS line. Cool water was provided for the young panicle - an effective method for overcoming the problems of high temperature during TGMS multiplication. The multiplication of TGMS in Viet Nam may also be done in mountainous areas (Sapa or Dalat) during the summer (Table 6).

Evaluation of TGMS lines

The characteristics of promising TGMS lines selected from the hybrid rice breeding network in Viet Nam are presented in Table 7.

The genetic combining ability (GCA) was as follows: 15 good male parents (tester) of the 10 TGMS lines, 7S (VNTGMS7S), 21S, CL64S and T29S give good GCA value for yield; the remaining TGMS lines give negative GCA.

TABLE 8

Various treatments to determine CSP and CFP of promising TGMS lines

TABLE 9

Sterility and fertility of pollens of TGMS after treatment at 25.5°C, 11 light hours under phytotron for 8 days (8-15 May 2000), HRRC

Note: F = fertility; SS = seed-set.
^a Date of observation

TABLE 10

Characteristics of CMS lines in summer 1998

The critical steriliy point (CSP) and critical fertility point (CFP) of six promising TGMS were determined under the following conditions:

• 24.5°C with 10 hours of light; and

• 25.5°C with 11 hours of light.

Three rice plants at stage 3-4 of panicle development were transfered from the field and planted in one plastic pot. When TGMS plants reached stage 5 of panicle development, the pots were used for treatment under phytotron.

Sterility and fertility pollens of the TGMS were studied (Table 9):

• 24.5°C, 10 light hours under phytotron for 8 days; and

• 25.5°C, 11 light hours under phytotron for 8 days.

Data on pollen fertility and seed-set at 24.5°C confirmed that:

• at 24.5°C, the six promising TGMS lines are partially fertile; and

• at 25.5°C, all TGMS lines are sterile.

TGMS lines were sensitive to temperature at stages 5 and 6, about 10 to 18 days before heading.

Under natural conditions, most TGMS lines complete sterility from 9 to 25 May. From 20 April to 15 May, the average day temperature is above 25.5°C. However, from 27 May to 5 June TGMS lines were fertile as a result of the low temperatures from 16 to 22 May (average temperature <24°C). The fertility and sterility of the six TGMS lines confirmed 25.5°C as the CSP to induce sterility.

There have been great efforts in the development of two-line hybrids with the TGMS lines available. Every season, between 1 000 and 1 500 test crosses were done between TGMS and high-yielding inbred lines. The yield potential of two-line hybrids was tested and selected hybrids were nominated for the national hybrid rice yield trials and the multiplication hybrid rice yield trials.

DEVELOPMENT AND EVALUATION OF NEW DEVELOPED HYBRIDS

Evaluation of CMS lines

CMS lines were introduced or extracted from the F₁ population and studied for stability and adaptability to Vietnamese conditions. Those with the best adaptability and good floral character were selected for the breeding programme. The characteristics of the selected CMS lines are given in Table 10.

TABLE 11

Characteristics of the promising hybrids selected in the National Hybrid Rice Yield Trials, summer 1998-99

Note: ns = non-significant

Result of breeding work and evaluation

The adapted CMS lines were used for crossing with available restorer and elite lines in Viet Nam. A total of 2 000 crosses were made in 1998-2000. The best hybrids for each regional area selected in the summer and spring crops in the national hybrid rice yield trials and multilocation yield trials (1998-2000) are presented in Tables 11, 12 and 13.

The hybrids, HYT57, VN01/D212, AMS24A/Que 99 and TN15, have been released for large-scale hybrid rice commercial production. Other promising hybrids are being studied for F₁ seed production and further evaluation prior to their release for commercial exploitation. Four hybrids with high yield and good quality were selected following the international hybrid rice yield trials over two years in four locations in Viet Nam (Table 14). The newly-developed hybrids have equal or higher yield than the hybrid check. However, all selected hybrids have higher quality than the commercial hybrids or inbred checks.

TABLE 12

Characteristics of the promising hybrids identified for different ecological locations, summer 2000

ADAPTED RESEARCH ON SEED PRODUCTION TECHNOLOGY

Research in seed production technology focuses on the synchronization of parental lines, including the effectiveness of old stored seeds on the growth duration of the parent. Research also concentrated on determining the appropriate structure of the male and female in the hybrid seed production plot and reducing the cost of hybrid seeds.

In an attempt to increase the hybrid seed yield of HYT57, GA₃ application was increased and several chemicals used to extend stigma exsertion or to extend the life of stigma. For good synchronization in F₁ seed production, promising CMS lines and restorers were studied for the following growth characteristics: duration from seeding to heading; leaf number in the summer; and effective temperature accumulation in the spring.

TABLE 13

Characteristics of the promising hybrids identified for different ecological locations, spring 2000

On the basis of these data and the experience gained in experimental hybrid seed production, the sowing gap between A and R lines was determined:

• AMS24A/Trac 64: A seeded when R1 reached 3.2 leaf stage.

• AMS24A/Que 99: A seeded when Que 99 reached 4.7 leaf stage.

• IR58025A/BR827: A seeded when R1 line reached 5.5 leaf stage in the spring or 2-2.5 leaf stage in the summer (7-8 days in the summer).

TABLE 14

Yield of promising hybrids selected from the International Hybrid Rice Yield Trials, 1999-2000

Note: ns = non-significant

The effect of old and new seeds of parental lines on growth duration was studied. Parental seeds stored for one to four seasons were used. The seeding date was selected on the basis of the growth duration of each parent in order that the flowering time be suitable for seed production.

In most cases (Table 15), the growth duration of male parent seeds stored for one season was one day shorter than that of fresh seeds. However, growth duration (seeding to flowering) of IR58025A and AMS24A using one-season-stored seeds was, respectively, two days and three days less than for fresh seeds. Similary, Zhenshan97A seeded with old seed had a growth duration one to two days less than the new seeds.

TABLE 15

Changing of growth duration (seeding to flowering) of some parental lines using fresh and old seed, spring 1999, HRRC

TABLE 16

Some characters of the typical patterns of seed production plot for Bo you 64 (AMS24A/IR9761-19) (HRRC, Ank Hanh, Hoai Duc, Ha Tay, spring 1997)

^a Highest yield.
^b Lowest yield.

Seed of AMS24A (produced in summer 1997) and AMS24 (summer 1998) were used for F₁ seed production in spring 1999. The growth duration with the old seed (produced summer 1997) was 3 days shorter than with AMS24A (summer 1998). However, in the summer, growth duration using old AMS24A seed (1-2 years in storage) is 5 to 6 days shorter than when using new seed (harvest in the spring of the same year).

Structure of population of female and male in hybrid seed production plot in spring 1997

Using AMS24A/IR9761-19 (Trac 64), it was determined that the ratio 2R:16A and transplanting space (AMS24A) 13x10 cm/hill gave the highest yield (2 544 kg/ha) (Table 16). This was confirmed in large-scale seed production from 1997 to 2001 for different provinces (Tables 17 and 18).

Progress has been made in establishing the structure of the male and female population of HYT57 hybrid. Studies at HRRC showed that in Ha Tay (summer), a ratio of 2R:12A and transplanting space (A line) of 15x17 cm/hill gave the highest yield (1 219 kg/ha) (Table 19). However, in Binh Dinh (south-central Viet Nam, summer), the ratio 2R:10A and transplanting space (A line) of 15x10 to 15x13 cm/hill gave the highest yield (1 930 kg/ha, 1 845 kg/ha, respectively) (Table 20).

More seedling nursery area (3 000-4 000 m²) is required for female seedlings. To protect seedlings from the cold in early spring, a nylon sheet is used to cover the seedbed after seeding or in low temperatures. Instead of seeding 1 kg seed of A line per 50 m² and transplanting at 5.8-6.0 leaf stage, 1 kg seed was seeded on 3 m² (density-seeded method) and transplanted at 3-leaf stage. Instead of 2 500 m² seedling nursery (female) per hectare, only 210 m²/ha is required with the density-seeded method. Synchronization studies confirmed that in the density-seeded method, the A line seeded when R1 Que 99 reached 5.2-5.4 leaves (compared to 4.6-4.8 leaves with the normal method). The results of the experiment are presented in Table 21

CT3 had the best synchronization: 2 901 compared to 2 860 kg/ha of the check. The density-seeded method of A line produced F₁ seed of AMS24A/Que 99, with a saving of 3 484 000 dong/ha (over 15% of total expenditure) compared to the current method. During 2001, the method was applied commercially in several provinces for hybrid seed production.

TABLE 17

Yield and yield components of male and female in seed production of AMS24A/Trac64 (IR9761-19) in different locations (1997-99)

TABLE 18

Yield and yield components of male and female in seed production of AMS24A/Que 99 in different locations (1996-2000)