STRATEGIES FOR BRIDGING THE YIELD GAP IN RICE: A REGIONAL PERSPECTIVE - R. C. Chaudhary^*

^* Chairman, Participatory Rural Development Foundation, Shivpur-Shahbazganj, Gorakhpur 27304, India

Rice in the Asia-Pacific Region, where 90 percent of it is produced and consumed, will remain the lifeline of the people. Demand for rice is expected to grow faster than the production in most countries (Swaminathan, 1998) so much so that by 2025 we will need 800 million tons of it annually. How this additional 300 million tons will be produced annually (Hossain, 1997) with less land, water, pesticides and manpower, is the crucial question for the next millennium. A depleted resource base and gradually eroding quality of land, water, and environment pose a threat of another magnitude.

The currency crisis in most Asian countries added another dimension to importing and exporting countries through cost of rice and/or investment in research and production. The yield deceleration, stagnation and decline observed in high-yield environments also gives a danger signal (Papademetriou, 1998). The rice area has already started declining in China, Malaysia, Bangladesh, the Red River delta in Vietnam, and other countries (Table 1).

2. APPROACHES TO BRIDGE DEMAND-PRODUCTION GAP

Approaches to bridge the gap of projected demand to current level of production could be by the expansion of rice area (horizontal expansion), increase of yield (vertical expansion), yield gap bridging, and reduction of yield losses. Horizontal expansion is often followed for additional production but in the Asia-Pacific Region now land area is diminishing (Table 1, Fig. 1). There is hope only from Africa and Latin America as more than 96 percent of the suitable rice land is remaining unutilised (Chaudhary and Tran, 1999). The vertical expansion approach by breaking yield barriers and by the use of already released varieties is the immediate possibility. Further, the New Plant Type (NPT) or Super Rice, hybrid rice, and genetically engineered transgenic rice are the additional possibilities. The yield gap bridging i.e., filling the gap between best experimental yields and those that farmers can achieve is promising. But due to its complexity, there are different views regarding avenues for increasing rice production (Duwayri et al., 1998). Pingali et al., (1997) argued that the yield gaps in favourable rice ecologies are not significant for exploitation for increasing rice production. Under this situation further increase in yield is possible only with the deployment of new technologies, such as hybrid rice. The reasons for the presence of large gaps and levels of technology has to be understood, (Fujisaka, 1994). But the pre and post harvest yield losses, often as much as 49 percent, gives much hope for bridging the yield gaps in most countries.

Table 1. Rice Production (P), Yield (Y) and Area (A) in 1997, and Growth Rates in P, Y, and A, during 1987-97 in Asia-Pacific (Source: FAO-RAP Publ.1998/21).

Country	Production (P) (000 tons)	Area (A) (000 ha)	Yield (Y) (kg/ha)	Growth Rate (%) in (1987-1997)
				P	A	Y
Australia	1,352	164	8,244	6.2	4.5	1.6
Bangladesh	28,183	10,177	2,769	1.1	- 0.4	0.7
Bhutan	50	30	1,667	- 0.2	0.1	- 0.2
Cambodia	3,390	1,950	1,771	4.4	2.4	2.2
China	198,471	31,348	6,331	1.0	- 0.7	1.6
DPR Korea	2,347	611	3,841	- 5.1	- 1.7	- 3.3
Fiji	18	7	2,246	- 5.5	- 7.1	0.8
India	123,012	42,200	2,915	2.6	0.5	2.1
Indonesia	50,632	11,100	4,449	2.2	1.2	0.8
Iran	2,600	550	4,240	4.9	1.5	2.8
Japan	12,531	1,953	6,416	-	- 0.5	0.5
Laos	1,414	554	2,902	2.1	-	2.8
Malaysia	1,970	655	3,008	1.6	0.1	1.5
Myanmar	189,000	6,070	3,064	4.0	3.3	0.6
Nepal	3,711	1,511	2,455	1.3	0.5	0.9
Pakistan	6,546	2,316	2,827	3.3	1.2	2.1
P. N. Guinea	1	-	3,023	-	-	0.1
Philippines	11,269	3,840	2,933	2.7	1.8	1.0
Rep. of Korea	7,100	1,049	6,794	- 1.8	- 2.3	0.5
Sri Lanka	2,610	660	3,954	1.3	-	1.3
Thailand	21,280	9,932	2,143	1.3	0.2	1.1
Vietnam	26,397	7,021	3,760	5.5	2.4	3.1
Total	523,784	133,696	3,918	1.8	0.4	1.4
Rest of World	49,479	16,115	3,070	2.0	0.3	1.7
World	573,263	149,811	3,827	1.8	0.4	1.4

Figure 1. Contribution (%) of area and yield to rice production in Asia, 1965-96. Production figures above the yield (Source: FAOSTAT 1997)

3. SUPERIORITY OF YIELD GAP BRIDGING

While efforts are being made to raise the yield ceiling, there is even a more pressing need to address the problem of yield gaps (Duwayri et al., 1998). The yield gap reduction can be considered as a local solution to a global problem. It can bring in additional production with the additional incentives of cost reduction, poverty alleviation, and social justice and equity. While no major breakthrough is expected immediately, reducing the yield gap alone can provide an additional 60 percent more rice needed by the year 2025.

4. MEANS AND MODELS TO BRIDGE THE YIELD GAP

4.1 The Model

The narrowing of the yield gap in rice, requires integrated and holistic approaches, including appropriate concept, and policy intervention (Cromwell, 1996). If any one of these components is missing or weak, the yield gap in that area cannot be narrowed (Tran, 1996). Narrowing the yield gaps (Fig. 2) aims not only to increase rice yield and production but also to improve the efficiency of land and labour use, to reduce the cost of production, and to increase sustainability. Exploitable yield gaps of rice are often caused by various factors including physical, biological, socio-economic and institutional constraints, which can be effectively improved through participatory and a holistic approaches and action by governments (IRRI, 1998b). An integrated programme approach is obligatorily required. The narrowing of the yield gap is not static but dynamic with the new technological development in rice production, as the gaps tend to enlarge with the improvement of yield potential of rice varieties.

Figure 2. The concept of yield gaps among theoretical potential, experiment station yield, the potential farm yield and the actual farm yield (modified from Gomez, 1977).

4.2 Lessons from Some Countries

In Indonesia, the national rice yield increased by about 4.9 percent per year during 1967-77 and 4.3 percent during 1977-87 through various schemes. Indonesia sets a good example of setting up strong test-transfer centres for technology (Chaudhary, 1998). Vietnam became the 4^th largest exporter from a basket case (Le, 1998), highlighting the ownership policy reform, from government to family holdings. Various methods and models of technology transfer have been tried since the era of the “green revolution” that began in India (Chaudhary et al., 1998; Taimni and Verma, 1998). Compact block Front Line Demonstrations (FLD) were started in 1990. Egyptian rice yield increased from 5.8 t/ha in 1987 to 8.5 t/ha in 1997 (Table 2) where technology demonstrations got very intensive and yield gaps reduced (Badawi, 1998). In Australia, the concept of “Ricecheck” reversed the yield decline of 2.4 percent per year in 1967 to the current level of 10 t/ha (Lacy, 1998) due to a very efficient system of technology transfer. In U.S.A. the yield gap is small (David Mackill, personal communication). With no yield gap, the national yield of Greece reached 7.6 t/ha in 1996, setting a good example to be emulated by other countries.

Table 2. Egyptian Rice Yields (ton/ha) in Demonstration Plots, National Average Gap during 1988-1997 (Source: Badawi, 1998).

Year	Demonstration Fields	National Average	Yield gap
1988	9.90	6.07	2.83
1989	10.50	6.45	4.05
1990	10.43	7.29	3.14
1991	10.60	7.57	3.03
1992	10.64	7.67	2.97
1993	10.31	7.74	2.57
1994	10.45	7.93	2.52
1995	10.51	8.20	2.31
1996	10.29	8.35	1.94
1997	10.33	8.56	1.77
Mean	10.40	7.58	2.82

5. HANDLING BIOLOGICAL CONSTRAINTS AFFECTING YIELD GAPS

5.1 Stable Performing Varieties

Superior yielding varieties are available (Chaudhary, 1996), which can take farmers’ yield to 8.00 t/ha if grown properly. But their performance is variable due to a higher proportion of Genotype X Environment (G X E) interaction (Gauch, 1992; Chaudhary, 1996). While the genetic reasons of stability in the performance of varieties may be difficult to understand, yet there is a need to identify and release stable yielding varieties even on a specific area basis, in contrast to relatively less stable varieties but on wide area basis. There are strong genotypic differences among varieties for this interaction, and methods are available to select more stable ones (Gauch, 1992; McLaren and Chaudhary, 1998). The New Plant Type of rice (also called “Super Rice”), which has been developed by IRRI, may raise the present yield potential by 25-30 percent (Khush, 1995). Rice biotechnology, which has recently made considerable progress, may also provide an opportunity to increase rice yields in a more effective and sustainable manner. Hybrid rice has become a reality in China and also in India, Vietnam, Myanmar and the Philippines, and may pose less yield gap problems in the future.

5.2 Weeds

Weeds reduce rice yield by competing for space, nutrients, light, and water, by serving as hosts for pests and diseases, and even due to allelopathic effects. Under farmer’s conditions, yield losses (gaps) are heavy due to improper or untimely operations.

5.3 Biotic and Abiotic Stresses

Rice has been under cultivation for thousands of years. As a result it has become a useful host for a number of diseases and insect-pests, 54 in the temperate zone, and about 500 in tropical countries. Of the major diseases and pests, 45 are fungal, 10 bacterial, 15 viral, and 75 insect-pests and nematodes. Realizing the economic losses caused by them, efforts have been directed to understand the genetic basis of resistance. The host-plant interaction and other control measures do reduce losses proportionate to their use, which is one pointer to yield gaps.

5.4 Soil Problems

Rice is grown from 45°S to 50°N of the equator, and from below sea level to 2,500m altitude. The rice soils vary from sand to clay, 5 to 10 pH, organic matter from 1 to 50 percent, and salt content from 0.1 to 1 percent. Other than on normal soils, rice is also grown in marginal and problem soils where plants face nutrient deficiency and toxicity. Improper varieties and improper management results in heavy yield losses and resultant yield gaps. Technologies are developing fast to ameliorate such situations.

5.5 Soil Fertility and Fertilizer

Soil degradation and quality deterioration limit crop yield in many intensive farms in Asia. Changes in organic matter and soil nutrient supplying capacity, nutrient imbalance and multi-nutrient deficiency, waterlogging and iron toxicity, soil salinity and alkalinity, development of a hardpan at shallow depths are some of the major indicators of deteriorating soil quality. Yield gaps can be attributed to knowledge gaps also (Balasubramanian et al., 1998). Rice suffers from a mismatch of its N demand and N supplied as fertilizer, resulting in a 50-70 percent loss of applied N fertilizer. Two basic approaches may be used to solve this problem. One is by regulating the timing of N application based on needs of the plants, thus partly increasing the efficiency of the plant’s use of the applied N. The other is to increase the ability of the rice system to fix its own N through nodulin genes and bacterium genes.

5.6 Water and Irrigation

Most studies on constraints to high rice yield indicate water as the main factor for yield gaps and yield variability from experiment station to farms. A recent study conducted by the International Water Management Institute, estimates that by the year 2020 a third of Asian population will face water shortage. Next wars may be fought over water (Gleick, 1993). The growth rate in the development of irrigation has already declined (Barker et al., 1998).

5.7 Integrated Crop Management (Prescription Farming)

Based on the extensive and critical testing of rice varieties and crop management technologies, it is possible to develop “prescription rice farming” for individual farmers and individual situations. The concept was tested on a limited scale in Indonesia during 1996-1997. Integrated Weed Management practice and IPM increase yield and decrease cost of pesticides, cost of production, and risk to health and the environment. Other knowledge based techniques will also help (Price and Balasubramanian, 1998). Narrowing the yield gaps by improvement of crop management practices of small farmers in developing countries is often not an easy task. It is essential, therefore, that these practices should not be applied in isolation but be holistically integrated in Integrated Crop Management Packages (ICMPs) with flexibility to adjust to prevailing environmental, socio-economic and market conditions.

5.8 Post-Harvest Problems

The introduction of more efficient technologies for handling, drying, storage and milling rice at the village level is essential to reduce post-production losses. The present impressions are that post-production activities are labour intensive, as the operations involve hand harvesting, sun-drying before threshing, threshing by trampling, and wind winnowing. This results in poor quality of milled rice including grain discoloration. The physical losses are more in wet season harvests due to problems of drying and the use of antiquated mills. Basic beliefs are that people in communities whose livelihood is affected are likely to provide their own motivation for change to ensure increased benefit for themselves. It is also believed that the local farmers and entrepreneurs should therefore be given the opportunity to define their post-production needs and be consulted in the selection of appropriate technologies.

6. HANDLING SOCIO-ECONOMIC CONSTRAINTS

6.1 Risk, Cost and Return

Rice is a totally risky crop in ecosystems like rainfed, upland, and flood-prone lands. Even in irrigated ecosystems, it is prone to risks of pests, diseases and floods. This affects farmers who apply costly inputs like seed and fertilizers. Even economists, not the farmers alone, advocate diversification and maximizing income from sources not strongly connected to rice farming. The only technology that can give confidence to farmers to use inputs, and can encourage them to reduce yield gaps, is the availability of stress resistant rice varieties.

6.2 Credit

Availability of credit for the development of infrastructure, capital costs or even crop loans in sufficient amount and on time is a big constraint. Not only the lack of collateral but also the interest rates pose a problem to farmers’ access to credit. This also affects farmers’ input applying capacity and profit margin. Government policy, institutional framework and policy affect the credit availability to farmers (Cromwell, 1996). A proper policy intervention is a must to make farmers credit-worthy and get enough and on time to buy inputs on an annual basis. The example of crop insurance in India is a praiseworthy policy support system.

6.3. Tradition and Attitude

The current level of factor productivity, which is still declining, cannot sustain the food need of the growing populace. Thus, sustainability must be at an increasing productivity level. The major reasons for instability in productivity are weather aberrations, crop management practices, and the severity of the pests. Although varieties tolerant to environmental stresses, higher stability and superior pest resistance have helped stabilize production, yet there is sufficient scope for improvement in these aspects. The issue to ensure that there is no degradation of the resource base in terms of soil and water, as well as the biodiversity of rice types requires the setting of an index of productivity.

6.4 Input Availability

Fertilizers, especially nitrogen, play an important role in rice production and productivity. Farmers need adequate amounts of fertilizer at the right time for obtaining high yields. The supply of fertilizers needs to be decentralized to village markets and the quality of fertilizers should be assured. Small farmers are usually unable to buy sufficient quantity on time for application; hence the provision of village credit could greatly help them. Bangladesh Grameen Bank is an interesting example of providing rural credit to landless and resource-poor farmers. The loan proposals are received by the bank only on a group basis (at least 5 persons), focusing on technology loans, housing loans, joint loans and general loans (Dadhich, 1995). Use of quality seed is the first and foremost way of realizing the yield potential of the recommended technology. High quality pure seed ensures proper germination, crop stand, freedom from weeds and seed borne diseases. It is recognized in general, that quality seed ensures 10 to 15 percent higher yields under the same set of crop management practices.

6.5 Institutions

Availability of agricultural credit, inputs (seeds, fertilizers, pesticides) supply, availability and quality of contract services and machinery for different farm operations, and repair and maintenance services in rural areas will influence the rate of adoption of knowledge intensive technologies (Price and Balasubramanian, 1998). The government and private institutions associated with credit, input and pricing influence directly the adoption and level of their use, and thereby the yield level.

7. PLANNING TO BRIDGE THE GAP

CGIAR Centres like IRRI, CIAT, WARDA have changed gears and decided to come out of their ivory towers to listen to farmers (IRRI, 1996), and plan farmer-relevant research with their cooperation. Hopefully, future collaborative projects could involve collaborating institutions, training of local researchers on basics of yield gap bridging, strategic planning with local counterparts, development of operational plans, introduction of selected technologies, and extension success cases. Such a blueprint plan is long overdue.

7.1 Project components

The project components are shown below. However, rapid appraisal studies are undertaken initially where such information does not exist.

· Survey, analysis and prescription: - Systems perspective and system requirements - a consideration of all key factors and players to identify key intervention points.

· Technology resourcing: - Existing technologies from international, national and provincial institutions, including modern progressive farmers.

· Institutional arrangements: - Linkages including integration of activities with other disciplines, and to establish IO-GO-NGO-PO linkages.

· Communication: - Communicating the technology and knowledge-based practices.

· Critical research: - Bottleneck technologies and practices to explore opportunities for improvement.

The yield gap analysis has to be performed considering the uniqueness of the individual situation. Another interesting area of inquiry would be to study the relative magnitude of yield gaps in different yield-potential groups of rice, say within TV, HYV, hybrid rice, NPT rice. This is based on the hypothesis that it should be the minimum in hybrid rice, as the seed cost is high and the farmers take relatively better crop care including application of fertilizer, weeding and irrigation. This is where the methodology proposed by De Datta et al., (1978) needs to be examined critically and modified to answer the following:

· Characterization - yield gap (estimating potential yield levels in different production environments). Also stratification of relative magnitude of yield gaps in various yield potential groups, within TV, HYV, hybrid rice, NPT rice etc.

· Partition total yield gap into individual components of management, biological and socio-economic groups.

· Analysis - systematic approach to understand decision process and management practices

· Intervention points/measures - improve management efficiency and alleviate working conditions of farmers, especially women farmers.

· Decision-support systems and communication systems developed for bringing information-intensive technologies to farmers. Development of guidelines for potential extrapolation to larger groups and other areas.

The process of technology resourcing has to be done on a specific area and situation basis to come up with prescription farming.

· Technology resourcing (assessment of requirements, evaluation of available technologies, assistance in pilot programmes)

· Information and knowledge (database, training)

· Development of decision support systems.

Communication issues have been haunting development agencies in transferring the technologies to farmers and devising methods on how to communicate to farmers with knowledge-intensive technologies. More efforts are needed to increase impact through identification of appropriate ways for high potential rice production and utilization interventions and to promote their adoption through development and application of improved dissemination strategies.

7.1.3.1 Government (GO) schemes

The positive aspects of government extension services lie in early successes with simple seed-based technologies and promotion of objectives of the State. They are relatively well resourced and staffed, but they have negative points like staff responsibility for non extension activities, slow bureaucratic response, weak links with research, tendency to favour more advantaged farmers, and top-down focus.

7.1.3.2 Non-Government Organisation (NGO)

The positive aspects of non-government Organisations are strength in decentralized systems, less bureaucratic/more flexible, people and poor centred, articulate the needs of disadvantaged groups, community focus, and effective in community mobilization/motivation, and active where the State and market are absent. The negative points of NGOs are their small/restricted impact, distance from policy decisions, professional and technical limitations, infrastructure, coordination, accountability, and limited resources.

7.1.3.3 Private Organizations (PO)

The positive aspects of the private sector organizations are strength in centralized systems, resources and management skills, technical competence, less bureaucratic, more flexible and innovative, and clear objectives. There are a number of strong negative points that focus on non-profit development, market manipulation, questionable technologies, favour mostly large and resource advantaged farmers.

7.1.3.4 Participatory (GO-NGO-PO)

The government organizations (GO), non-government organizations (NGO) and private organizations (PO) and farmers may join hands to resource-test-demonstrate-adopt models. Given appropriate roles and a decision making process, this may be the most effective broad-based and sustainable approach. IRRI has put such proposals into practice recently (IRRI 1998a, 1998b). But we must consider the new agents of change positively, which lie in the partnership of NGO, PO, and GO. The question remains as to who are the most appropriate ones?

· Difficult to answer.
· Dependent on circumstances and technology.
· Still not well understood.

· Are these new agents of change more effective in promoting the impact of research results?
· Under what kind of circumstances and for what kinds of technologies?
· What are the most appropriate roles, responsibilities, and linkage mechanisms?

· Is it feasible?
· What can be done to encourage partnership formation?
· Under what kind of circumstances and for what kinds of technologies?
· What are the most appropriate roles, responsibilities, and linkage mechanisms?

· GO + NGO +PO Partnerships
· Research +NGO/PO partnerships
· Hybrid diffusion system
· Utilizing new tools.

Learning from successful farmers shows the relative importance of biophysical and socio-economic constraints. The hypothesis in this case is that farmers with least yield gap have used sets of technologies and knowledge adapted to their locations in a dynamic decision-making process that is uniquely different from farmers with high yield gaps. Tapping the knowledge of successful farmers is considered very effective in resourcing and spreading location specific and superior technologies. Appropriate national agencies must learn all this gamut of technologies, knowledge and experience to transfer to the bulk of other farmers.

7.2 Policy Support

Government policies provide the environment for research investment, improve productivity, alleviate poverty, ensure systems’ sustainability, protect the environment, and provide food security. Various types of policy interventions are needed which influence investments in research, assure availability of inputs and credit, and introduce a crop insurance policy to encourage the use of inputs and reduce risks. It is therefore imperative that through appropriate policies, socio-economic adjustments should be affected in terms of input-output pricing, institutional support, and to redress the needs of rice farmers in order to complement the technological gains.

7.3 Linkages

Linkages within and outside the country are important aspects of the project, for which the following list may be relevant:

· Linkage with the efforts of NARS in the Asia-Pacific Region
· Linkage of GO-NGO-PO-Farmers
· Linkage with IRRI’s projects RE4, CREMNET and RTDP.
· Linkage with FAO’s projects in this area.
· Linkage with other IARCs on a case by case basis.
· Linkage for funding support with donor consortiums.

Badawi, A.T. 1998. Sustainability of rice production in Egypt, IRC 98/7-2, Cairo, Egypt, 12 pp.

Balasubramanian, V., Morales, A.C., Cruz, R.T. and Abdul Rachman, S. 1998. On-farm adaptation of knowledge-intensive nitrogen management technologies for rice systems. 1-12. In: Nutrient Recycling in Agroecosystems; Kluwer Acad. Publ. Netherlands.

Barker, R., Dae, D., Tuong, T.P. Bhuiyan, S.I. and Guerra L.C. 1998. The outlook for water resources in the year 2020: challenges for rice research on water management in rice production. 2 pp. IRRI, Los Baños, Philippines.

Chaudhary, R. C. 1996. Internationalization of elite germplasm for farmers: Collaborative mechanisms to enhance evaluation of rice genetic resources. In: New Approaches for Improved use of Plant Genetic Resources; Fukuyi, Japan; pp. 26.

Chaudhary, R.C. 1998. Indonesian Coordinated Rice Testing Network (ICRTN). World Bank-ARMPII, CRIFC, Bogor, Indonesia. 152 pp.

Chaudhary, R.C., Reddy, A.P.K., Balasubramanian, V. and Roy, J.K. 1998. Partnership internationally: An overview of India’s experiences in rice research. 483-509 pp. In: Rainfed Rice for Sustainable Food Security. CRRI, Cuttack, India.

Chaudhary, R.C. and Tran, D.V. 1999. Can Africa be the future rice supplier for Asia? In: Proc. 4^th Asian International Rice Conference, Cebu, Philippines, 29 pp.

Cromwell, A. 1996. Governments, farmers and seeds in a changing Africa. CAB International, Wallingford, Oxon, U.K. 174 pp.

Dadhich, C.L. 1995. Grameen bank: The pros and cons. In: Proc. New Deal for Self Employed: Role of Credit, Technology and Public Policy. 30:1-2.2

De Datta, S.K., Gomez, K., Herdt, R.W. and Barker, R. 1978. A Handbook on the Methodology for an Integrated Experiment on Rice Yield Constraints. 60 pp. IRRI, Los Baños, Philippines.

Dudung, A.A. 1990. Modernizing rice farming: Indonesia’s experience in conducting the green revolution. 265-274 pp. In: Proc. 17^th International Rice Commission, Goias, Brazil.

Duwayri, M., Tran, D.V. and V.N. Nguyen 1998. Reflections on yield gaps in rice production: How to narrow the gaps. International Rice Commission, 98/7-12 Session, Cairo, Egypt; 21 pp.

Fujisaka, S. 1994. Bringing together rice farmers’ science and formal agricultural science. IRRI, Los Baños, Philippines. 34-35 pp.

Gauch. H.G. 1992. Statistical Analysis of Regional Yield Trials: AMMI Analysis of factorial Designs. 278 pp. Elsevier Publ. Co.

Gleick, P.H. (ed.) 1993. Water in Crisis: A Guide to the World’s Fresh water Resources. Oxford University Press, New York.

Gomez, K.A. 1977. On-farm assessment of yield constraints: methodological problems. 1-16 pp. In: Constraints to high yields on Asian rice farms: an interim report. IRRI, Los Baños, Philippines.

Hossain, M. 1997. Rice Supply and Demand in Asia: a socio-economic and bio-physical analysis. In: Applications of Farm Approaches at the farm and regional levels. Kluwer Academic Publisher, 263-279 pp.

IRRI, 1996. Listening to the Farmers. 93 pp. IRRI, Los Baños, Philippines.

IRRI, 1998a. Bridging the Knowledge Systems of Rice Scientists and Farmers. CREMNET-IRRI Los Baños, Philippines. 19 pp.

IRRI, 1998b. Farmer Participatory Research and Best Inbred Variety. CREMNET-IRRI Los Baños, Philippines. 11 pp.

Khush, G.S. 1995. Modern varieties - their real contribution to food supply and equity. Geojournal 35 (3): 275 - 284.

Lacy, H.N. 1998. Ricecheck a collaborative learning approach for increasing productivity. In: Temperate Rice: Achievements and Potentials. Vol. II. pp. 247-254, Yanco, Griffith, Australia.

Le, H.N. 1998. Rice production in Vietnam and the policies to promote its development. 19^th Session of International Rice Commission, Cairo, Egypt.

McLaren, C.G. and Chaudhary, R.C. 1998. Use of additive main effects and multiplicative models to analyze multi-location rice varietal trials. Oryza 33(4): 306 - 318.

Papademetriou, M.K. 1998. Current issues of rice production in Asia and the Pacific. International Rice Commission, 19^th Session, Cairo, Egypt; 18 pp.

Pingali, P.L., Hossain, M. and Gerpacio R.V. 1997. Asian Rice Bowls: The Returning Crisis? IRRI-CAB International, 341 pp.

Price, L.M.L. and Balasubramanian, V. 1998. Securing the future of intensive rice systems: a knowledge-intensive resource management and technology approach. In: Sustainability to Rice in the Global Food System. 93-204 pp. Pacific Basin Study Centre, Davis, California USA - IRRI, Los Baños, Philippines.

Swaminathan, M.S. 1998. Issues and challenges in sustainable increased rice production and the role of rice in human nutrition in the world. International Rice Commission 98/4-2, Cairo, Egypt, 23 pp.

Taimni, B.K. and Verma, K.P.S. 1998. Special rice production programme in India. 510-516 pp. In: Rainfed Rice for Sustainable Food Security. Central Rice Research Institute, Cuttack, India.

Tran, D.V. 1996. Evolution of rice yield in Asia and the Pacific. Expert Consultation on Techn. Evol. and Impact for Sustainable Rice Prod. in Asia-Pac. FAO, Bangkok, Thailand. 18 pp.