Chapter VII - China case study 2: Cold-resistant lucerne (Medicago sativa) for northern Xinjiang - Jichun Min

Summary

Large areas of lucerne have been developed for hay at Altai, near Burjin, in the north of Xinjiang - an arid region with very cold winters. Only one cultivar (a local landrace) was in use and it was deemed desirable to have a wider genetic base. Introduced supposedly cold-tolerant cultivars failed to overwinter. Local selection has produced an improved cultivar, registered by the Chinese Herbage Cultivar Registration Board as ‘Xinmu No. 3’. It is well adapted to the area and is more productive than the cultivar already in use. A system of seed multiplication and maintenance of mother seed has been installed. Improvement of lucerne to suit local conditions is obviously feasible, and this work should have application to areas of similar ecology within the subregion. Uptake of new cultivars has been slow in the Project that was the main target of the work; partly because of lack of training and experience on the part of the herders involved, who still use the cheapest seed available. It may, however, be more readily accepted by more experienced communities. Field testing and experience in the project has shown that there are many constraints other than genetic ones in the production of lucerne: correct field levelling, use of clean seed and field hygiene to control Cuscuta, general careful husbandry and adequate fertilizer are all necessary if reasonable crops, adequate to cover the costs of infrastructure and water, are to be attained.

Introduction

The area of World Food Programme (WFP) Project 2817, for which this work was mainly carried out, is described in Chapter VI. Lucerne, Medicago sativa, is a crop of very ancient cultivation in the irrigated areas of Xinjiang. It was probably introduced when improved horses were imported from Central Asia. The oases of Xinjiang lie on the ancient Silk Route, which led through the original homeland of lucerne, in the historical region of Media and adjacent lands in Asia Minor. Several landraces have developed over the centuries, with notable differences between those from the colder northern areas of the Djungar basin and those from the Tarim basin, which is south of the Tien Shan Range and where winters are less harsh. Several wild relatives of lucerne occur in the better-watered areas of Xinjiang’s mountains, notably M. falcata.

In the 1980s, the Animal Husbandry Bureau developed 25 000 ha of irrigated land for hay production on sandy-gravelly soils unsuited to arable cropping (Li, Yuang and Suttie, 1996) in Altai Kazakh Prefecture in the extreme north of the Region, under Project 2817. The work was assisted by the World Food Programme (WFP) and technical inputs were funded by the United Nations Development Programme (UNDP) and executed by the Food and Agriculture Organization of the United Nations (FAO). The scheme was in production by the end of the decade. The livestock activities of the Project were described in an earlier chapter. For a map of the Project area, see Figure 6.2.

While the currently used cultivar, ‘Beijang’, was admirably adapted to the local conditions, reliance on a single cultivar of one species over so large an area gave rise to some concern. The Project covered four areas (Altai, Fuhai, Dure and Burjin), and formerly lucerne had been cultivated in scattered fields. In addition, cv. Beijang is susceptible to some fungal diseases and this was exacerbated by imperfections in the micro-levelling of the newly-formed irrigated fields; plants in tiny depressions where water lay longer were frequently attacked by fungi, often giving rise to a “little leaf” effect through proliferation of many weak stems caused by damage to the crown. A literature search was carried out (by R.W. Brougham, FAO consultant under the UNDP/FAO project) to identify cold-tolerant, disease-resistant lucernes, and a large number of samples, mostly from North America, were introduced for screening. Their testing was undertaken by the Xinjiang Agricultural University, with the main site at the Altai part of the scheme.

The initial growth of many of the introductions was impressive and their first year performance far outstripped the local control (cv. Beijang). Next spring, however, none of the introductions survived at Altai - only the control was alive! The project sites, on the desert fringe, have little or no snow cover in winter so the young plants had no protection; perhaps they had been selected in areas with snow cover. It later transpired that earlier introductions from Russia had failed in a similar way. There was, therefore, no easy way to diversify and improve the lucernes in use by importation of commercially available cultivars. After discussions with the fodder specialists of Xinjiang Agricultural University, the Grassland and Pasture Crops Group of FAO/AGPC agreed to provide some support so that the University’s ongoing work on breeding and selection of lucerne could be intensified.

Testing sites

Although the climate at Urumqi (see maps, Figures 6.1 and 6.2) is very harsh, it is less so than that of the project production sites. Urumqi, 43°47’ N, 85°37’ E, at 919 m altitude, has an annual mean temperature of 7°C and a January mean minimum of -20°C; precipitation is 302 mm. Long-term data from project sites are not available. The nearest site for which data are available is at Fuyun, which is higher than the irrigated areas and receives more precipitation: project sites receive less than 100 mm annually. Fuyun is at 46° 59’ N, 85°43’ E, at 1294 m altitude; its mean annual temperature is 3.5°C, January average minimum is -26°C; precipitation is 198 mm. The temperature and precipitation at the two sites are shown graphically in Figures 7.1 and 7.2.

The main field testing was carried out at Altai, with breeding and other work at Urumqi to facilitate access to facilities and specialized staff.

Development of ‘Xinmu no. 3’ lucerne

In 1995, when they greened up in spring, 33 plants were selected from a fouryear- old plot of cv. Spredor 2 lucerne at Urumqi. Spredor 2 is a cultivar released by Northrup King in 1974. Its parentage is Travois, Rambler and Vernal, which are cold-tolerant cultivars with Ladakh, M. falcata, Siberian and Cossack among their parents. Spredor 2 has variable flower colour; it is highly resistant to bacterial wilt and moderately resistant to verticillium wilt and fusarium wilt. The Spredor 2 at Urumqi had been sown in 1990 and grown unprotected through the subsequent winters; the selection was made among the survivors. These were open pollinated and the seeds mixed to form line 9501. Some stems were taken as cuttings and taken to 183 Farm, Beitun, Altai (hereafter referred to as Altai) in August for cold tests. Splits of twelve mother plants were grown in a greenhouse to speed up seed production; seed was harvested in November, 1995.

FIGURE 7.1. Summary average meteorological data for Urumqi.

FIGURE 7.2. Summary average meteorological data for Fayun.

Some survivors (at Urumqi) from the FAO introductions were crossed with the local standard cv. Xinmu No 1, but, since rapid results were required to assist the Altai Project 2817 scheme and the work would have required at least 11 years, this was not followed-up under FAO financing.

Four cultivars were chosen for testing at Altai and Urumqi from 1996: line 9501, Beijang, Xinmu No. 1 and Spredor 2. These were sown in randomized blocks (Plate 41) with three replications at both sites in plots of 5.63 m² with a 30 cm row spacing and a seed rate of 3 kg/ha. Harvest was at early flowering (2-3 percent) with two-and-a-half cuts at Urumqi and two at Altai. The last cut was taken one month before growth was expected to stop. For dry-matter estimation, 500 g samples were air-dried. The trials received five to six weedings, three to four hoeings and five to six irrigations annually. Yield data are given in Tables 7.1 and 7.2.

Line 9501 was the highest yielder throughout the trials at both sites. In both cases, second-year yields were much higher than those of the seedling or third year - this may be due to the lack of maintenance fertilizer - normal practice for the area.

Testing for cold resistance was done at both sites. Surviving and dead plants were counted after greening-up each year; with three counts made, since some plants that were injured by low temperatures, but had not died, greened-up 3 to 20 days later than normal plants. Plants that had not greened up at the first counting were marked; if they greened up at the second or third counting, they were added to the survivors; those which had not greened up by the branching stage were counted as dead. Results for the two sites are given in Table 7.3. Survival was very good throughout; as all entries in the trial were, of course, known to be adapted to local conditions. Survival of Spredor 2 and Beijang at Urumqi in the third year was much poorer than that of line 9501 and Xinmu No. 1, but at Altai all survival rates were similar.

Plate 41. Lucerne trial plots in Urumqi.

TABLE 7.1
Yield trial at Urumqi over three years (yield in t/ha of air-dry material).

TABLE 7.2
Yield trial at Altai over three years (yield in t/ha of air-dry material).

TABLE 7.3
Comparison of winter survival rate (percent).

TABLE 7.4
Effect of removing snow cover at Urumqi, 1997.

The effect of removal (by brushing) of any snow cover from the third replicate was studied between November and April of the establishment year (Table 7.4). Snow removal delayed greening-up by a few days and caused a small decrease in survival.

Overwinter survival, of course, reflects more than cold tolerance: disease susceptibility is also involved. For both, line 9501 was superior. Snow removal led to a mortality of between three and six percent, with no difference in winter survival between line 9501 and Beijang (Table 7.4).

As part of the characterization of the new cultivar for registration, phenological data (Tables 7.5 and 7.6) and information on the approximate forage composition (Table 7.7) were collected. Line 9501 (Xinmu No 3) has at least as good a feeding value as Beijang.

TABLE 7.5
Growth stages of line 9501 in Urumqi.

TABLE 7.6
Comparison of plant height, Urumqi 1998 (cm).

TABLE 7.7
Proximate analysis of line 9501 and cv. Beijang (percentage of dry matter).

NOTE: (1) NFE = Nitrogen-Free Extract

TABLE 7.8
Field-scale yields at two sites (yield in t/ha of air-dry material).

As formal testing advanced, field-scale trials were installed at Beitun/Altai and Urumqi, under conditions similar to those used by herders, to see how the selection performed as a possible commercial cultivar. As shown in Table 7.8, line 9501 performed well at both sites.

Studies on other cultivars

A few plants of other FAO introductions had survived at Urumqi; these were studied in observation plots at Urumqi from 1996 to 1999, with Xinjiang Diaye as control. None were really promising (see Table 7.9). Recently (2002), some new cultivars from Montana, USA, have been introduced and are currently being assessed at Xinjiang Agricultural University in Urumqi.

Seed multiplication

Seed production of line 9501 was a priority from the outset in order to provide enough for proper testing; once the line showed promise, provision of breeder’s and foundation seed was organized so that these could be supplied to producers. Since isolation, protection from livestock, avoidance of volunteer plants and access for supervision are all necessary on seed production plots, suitable sites were limited and small, but, starting from the few plants grown in the greenhouse in 1995, over 10 kg of breeder and foundation seed was produced in 1997, and a total of 35 kg by 1998. The improved cultivar 9501 has been registered by the Chinese Herbage Cultivar registration Board as cultivar Xinmu No. 3. Following another FAO project (FAO/TCP/CPR 0065), Xinjiang Agricultural University started (2002) multiplying seed on various seed farms, and large quantities were expected to be available in 2003 or 2004.

TABLE 7.9
Comparison of introduced material (t/ha green matter).

Lucerne seed production in Altai has been a problem for a long time. Seed production bases were set up there in the 1970s, but the level of technology was low, cultural practices were unsuitable for good seed production, and infestation with dodder (Cuscuta sp.) became serious. Unfortunately, much of this seed was used in the initial years of the Altai scheme and much of the land is now contaminated with dodder. The dodder infestation occurred because there was no scientific seed production and no attempt to eliminate dodder systematically. Cuscuta seeds can survive for twelve years in the soil and can be spread by irrigation water, as well as through animal droppings. The seed production base at Dulati had to be closed in the early 1990s. For Project 2817, following the advice of Dr Brougham, a seed production base for Xinmu No. 1 was established in the early 1990s and nearly 2 tonne of seed harvested, but this base was closed because of lack of funds.

Lucerne seed is not an attractive crop in Xinjiang. Yields are low, about 150 kg/ha is common on commercial farms (although Xinjiang Agricultural University farm has regularly been achieving seed yields of 600-700 kg/ha, and yields in excess of 1000 kg/ha are expected), and farmers are unwilling to pay for quality. The cultivar Xinmu No 1 was released in 1987; since then, seed has been provided to more than forty farms for multiplication but only two farms have produced seed and multiplied the cultivar, and total extension has been only 100 000 ha. The main reason is that field crops - cotton, oilseed rape, sugar beet and cereals - are easier to grow and more profitable.

It has now become necessary for a well supervised three-step production system (breeder seed Þ foundation seed Þ certified seed) to be used for future lucerne seed production. Clean, dodder-free, healthy seed of adapted varieties is the key to sustainable, high yielding lucerne production in Altai. Farmers are now buying cheap seed from other parts of China, but that seed is of cultivars that are not sufficiently cold-tolerant, and the seed is not clean. A greater extension effort will be required by Project 2817 authorities, together with the re-opening of their base for seed multiplication, if the problems associated with poor seed are to be overcome. The herders of the project had no experience of crop and fodder production before the project’s inception; they were transhumant stock rearers. Every aspect of cultivation is new to them, and it is unfortunate that they have not yet appreciated the importance of proper choice of cultivars and maintenance of clean healthy seed. Even more so since the importance of animal breeding and health is well understood by them.

To assure long-term preservation of the seed base for Xinmu No 3, sixteen lines have been planted in isolation at stations throughout Xinjiang. Production of breeder seed is undertaken at five sites, including Chanji and Hami. This also facilitates the introduction of the new cultivar to other parts of the region: Xinjiang covers about 1 600 000 km² and distances are vast. Recent efforts by Xinjiang Animal Husbandry Bureau and especially by Xinjiang Agricultural University should ensure that adequate quantities of seed will become available in 2003-2004.

Discussion

The very cold, arid areas of northern Xinjiang pose a problem when broadening the genetic base of lucerne cultivation, especially since introduction of cultivars from elsewhere does not succeed. Earlier work (development of cvs Xinmu No 1 and Xinmu No 2) showed that considerable progress can be made by working with local material. The work described above shows that introduced material can have a very positive role in lucerne improvement, at least insofar as material with some M. falcata in its background is concerned. The cultivar Xinmu No 3 has shown itself to be superior in yield to the landrace currently in use, and well adapted to the conditions and methods of husbandry used locally. It may well prove to be valuable over a much wider area in the colder, arid tracts of northern China and northeastern and central Asia.

The practical application of the work, however, shows clearly that there are major factors limiting lucerne production in Project 2178, other than the cultivars in use. The main factors are associated with proper husbandry and irrigation:

• lack of care with seed quality at the outset of the scheme has led to serious infestation with Cuscuta. This will be very difficult to control, and impossible unless a clean seed supply is assured and strict crop hygiene insisted upon;

• correct land levelling and in-field water management is essential to assure an even stand and lessen the challenge from fungal disease;

• it is likely that maintenance dressings of phosphatic fertilizer should be used to prolong the productive life of the crop and avoid the drop seen after the second year; and

• the poor uptake of seed of improved cultivars means that the majority of herders still use unimproved, and probably unclean, seed because it is cheapest.

These omissions are particularly serious in irrigated farming, where high yields per unit of area are desirable in order to pay for water and maintenance of infrastructure. The herders, who have never cultivated before, have made great progress in haymaking, but there is still a great deal of training to be done if they are to make good, sustainable use of the irrigation infrastructure and of the well adapted cultivars now available to them.

It is still too early to say how the new cultivar might be accepted in other lucernegrowing areas of the region. While uptake of new cultivars has been very slow among the inexperienced growers of Project 2718, there may be better reception in the more traditional lucerne-growing communities.