ITEMS FROM NEPAL

NATIONAL WHEAT RESEARCH PROGRAM

Bhairahawa, Nepal.

M.R. Bhatta, D.R. Pokharel, Ashok Mudwari, and B.R. Thapa.

During the 1996-97 crop season, bread wheat occupied an area of 667,720 ha with a total production of 1,063,000 metric tons and average productivity of 1,590 kg/ha. The total wheat area, production, and productivity increased by 2.20, 4.90, and 2.60 %, respectively, compared to the 1995-96 wheat season. Currently, more than 90 % of the wheat area is under improved varieties. Weather conditions during the preharvest period were favorable for excellent growth and development of wheat in Nepal. The absence of hot, dry, desiccating winds during the postanthesis period resulted in better grain filling in the plains areas. However, in the eastern part of Terai, rains with hail during harvest time resulted in significant damage to the wheat crop and also deteriorated the quality of wheat seed for some farms. Low productivity of wheat is due to low fertilizer use by wheat growers; a low farm-gate price for wheat; late planting due to late a harvest of the rice crop, low seed replacement; and diseases, particularly the foliar blight complex caused by B. sorokiniana and Pyrenophora tritici repentis.

The major wheat cultivars currently popular are Nepal 297, UP 262, BL 1022, Bhrikuti, BL 1135, and Triveni in the Terai region; and Annapurna-1, Annapurna-3 (both Veery 'S'), Annapurna-4, and RR 21 in the hills.

Four new wheat cultivars released.

BL 1496 (pedigree: PRL"S"/TONI//CHIL"S"), named as Rohini,
NL 713 (pedigree: CPAN169/HD2204), named as Achyut,
NL 665 (pedigree: LIRA/FUFAN//VEE#5"S"), named as Kanti, and
WK 685 (pedigree: PGO/SERI), named as Pasang Lahmu.

The former two are resistant to leaf rust with the Lr34 complex, moderately resistant to Helminthosporium leaf blight, and recommended for Terai areas. Kanti and Pasang Lahmu are moderately resistant to yellow rust and adapted to hill environments.


Wheat breeding activities.

The major objectives of the wheat breeding and varietal improvement program in Nepal are to develop wheat cultivars that fit well into the rice­wheat cropping pattern, have high-yield potential, are resistant to multiple diseases (leaf and stripe rusts, major foliar blight pathogens, and loose smut), and are tolerant to post anthesis heat and drought stresses. The rice-wheat cropping system comprises more than 84 % of the total wheat area. Wheat breeding activities during 1996-97 included regular hybridization work involving selecting parents for specific resistance genes (foliar blight, leaf rust, stripe rust, and post anthesis heat and drought stress); screening and selection of segregating generation lines; multilocation evaluation of advanced genotypes in the form of screening nurseries and yield trials, and farmers' field trials; and varietal maintenance to produce nucleus and breeder seeds.

Some of the high-yielding genotypes identified during 1996­97 with resistance to major diseases are NL 783 (pedigree: Gaa/Kea//Gaa), BL 1724 (pedigree: Para2//Jup/Bjy/3/Vee#5/Jun/4/Nac), NL 781= Attila, NL 872 (pedigree: Chil/2*Star), NL874 (pedigree: Cno/Prl//Chil/Gaa, BL1794=Vee/Lira//Attila), and NL867 (pedigree: Buc/Bjy/4/Fct/3/Gov//Az/Mus/5/Buc/Bjy). Several lines resistant to foliar blight disease have been developed at the National Wheat Research Program, Bhairahawa, and are available for distribution on request.

Wheat disease situation.

Leaf rust is under control with the deployment of cultivars with the Lr34 gene complex. Leaf rust severity in previously released cultivars with Lr13 and Lr23 combinations was found to be very low in recent years. Two species of foliar blight pathogens, B. sorokiniana and Pyrenophora tritici repentis, are the ones causing blight symptoms in wheat. This year, leaf and stripe rust incidences were less and appeared late in the season even in susceptible cultivars. Helminthosporium leaf blight severity also was low because of the absence of rain during the vegetative period. Virulence for Lr26 and Yr9 has been detected at a moderate level.

Surface/relay seeding of wheat.

The new technique of zero-tillage wheat cultivation was developed at the National Wheat Research Program for low land rice areas where wheat cultivation was impossible because of excessive moisture following the rice harvest. The technique involves soaking wheat seed in fresh water for 8 to 10 hours, mixing soaked seed with fresh cow dung, and then broadcasting the seed in the standing rice 1 week before harvest or surface seeding just after rice harvest. Fertilizers can be applied successfully 10 to 20 days after seeding. This technique is being popularized among low-land rice farmers to bring one-third of the rice-fallow area under rice-wheat.