Items from Nepal.

ITEMS FROM NEPAL

NATIONAL WHEAT RESEARCH PROGRAM

Bhairahawa, Nepal.

M. R. Bhatta.

Crop Season. Weather conditions during wheat season were fairly dry and cool, which favored excellent growth of wheat in the irrigated area of Terai. However, in the hills, moisture stress was severe because of insufficient rains resulting poor yields. Week-long, westerly dry winds during the peak grain-filling period in the Terai reduced kernel weight to some extent.

Area and production. Wheat crop occupied an area of 640,802 hectares, the total production was 1,086,470 metric tons, and the average productivity was 1,695 kg/ha during the 1998-99 wheat season. Wheat area, production, and productivity increased by 0.12 %, 5.4 %, and 5.3 %, respectively, compared to the 1997-98 wheat season. Wheat yields have increased steadily since 1995-96, and the present national average yield is 1.695 tons/ha.

Wheat varietal diversification in the country. Since the inception of National Wheat Research Program in 1972, a number of wheat cultivars with different genetic background have been released, and many of them have been accepted widely by the farmers. Newly released wheat varieties are more tolerant to the foliar-blight complex of diseases, the number one factor limiting wheat production in the terai of Nepal. Bhrikuti (pedigree: CMT/COC75/3/ PLO//FURY/ANA) has become very popular among wheat growers because of its high yield potential and disease resistance. Other varieties currently popular are Nepal 297, BL 1022, Rohini, UP 262, and Annapurna-1.

The major objectives of the wheat-improvement program are to develop wheat cultivars that fit well into the rice-wheat pattern with high yield potential; resistance to multiple diseases (leaf and stripe rusts, foliar blight, and loose smut); tolerance to postanthesis heat and drought stress; and sterility.

Wheat-breeding activities during 1998-99 included regular hybridization work involving selected parents for specific purposes; screening and selection on segregating generation lines; multilocation evaluation of advanced genotypes in the form of screening nurseries; and yield trials, along with farmers' field trials. Varietal maintenance produces nucleus and breeder seeds of currently popular varieties.

New wheat cultivar released. BL 1473 (NL 297/NL352) was released for the Terai areas under timely sown and late-sown, irrigated conditions. BL 1473 is resistant to leaf and stripe rusts and moderately resistant to Helminthosporium leaf blight, is very similar to Sonalika in maturity, and has bold amber grains.

 

Rice-wheat system research.

The rice-wheat cropping system is the most predominant one and occupies nearly 0.5 x 106 ha. Roughly, more than 84 % of the wheat area is sown after rice. Mid-November is the optimum planting time for wheat, and a delay in planting has become the main yield-limiting factor, because the management efficiency (fertilizers and irrigation) is reduced greatly. Causes of late planting of wheat include an excess/depletion of soil moisture and a long turnaround time. Research into making timely planting of wheat possible and increasing production with reduced cost of production is in progress.

Relay seeding. The prerequisite for relay seeding is excess soil moisture at planting, so fields are irrigated if soil moisture is depleted. Wheat seeding is done 3-5 days before the rice harvest. The harvested rice plants are spread uniformly to cover the entire plot and let dry for about a week. Relay planting lessens bird damage, protects soaked seed from drying, and conserves soil moisture. On-station and on-farm research conducted since 1990 revealed its superiority over conventional practices and found relay seeding suitable for poorly drained, heavy-textured soils where normal land preparation is very difficult. Covering seeds for about 1 week with harvested rice plants improved wheat yield. Yields were better, and 1,000-kernel weight and net benefits also were improved. Relay seeding could be an alternative technology to change nontraditional wheat fields (rice-fallow) to the rice-wheat system.

Surface seeding. This method is similar to relay seeding in all respects except that the wheat is seeded after harvest of the rice crop. Leaving longer stubble improved the crop stand and grain yield. An increase in N use efficiency was found when equal amounts of N were applied 20 and 30 days after seeding. A severe infestation of weeds was observed when N was applied before 10 days after seeding. Improvement in 1,000-kernel weight contributed to higher yields.

Surface seeding onto saturated soil. This type of seeding is a reduced-tillage method, where the field is plowed once or twice and then leveled, irrigated, and drained immediately. Soaked or dry wheat seed treated with fresh cowdung were planted late in the afternoon This technology was compared with surface seeding and the conventional practice of wheat establishment. Similar to surface seeding, this method is statistically superior to the conventional practice in grain yield. Because the seed sticks to the soil surface at planting, emergence is excellent and uniform. Weed intensity was minimized, and even rat damage was reduced considerably. Improvement in 1,000-kernel weight was observed.

Disease situation. Because of the dry season, incidence of Helminthosporium leaf blight and leaf rust were low compared to previous years. Annapurna-1 (Lr26) had a 30S/MS to 60S leaf rust severity, Sonalika had 20S, and Bhrikuti (Lr34+Lr26) had 10MS severity in the disease screening nurseries. Yellow rust severity also was low because of dry weather; varieties with Yr9 showed a 50S to 60S severity.