Participatory on-farm evaluation of wheat genotypes

In wheat development programs, the evaluation and identification of superior genotypes  is the first and leading step in a crop improvement program. Coordinated Farmer’s Field Trial (CFFT) was conducted during the three successive wheat growing season of 2010/11, 2011/12 and 2012/13. In CFFT six different wheat genotypes were planted in different outreach sites of research stations of Nepal Agricultural Research Council (NARC) at varying geographical regions. CFFT was conducted according to standard recommended practices of wheat at farmers’ field with different sets of genotypes for Terai and hill. In CFFT for Terai Tar and Lower valley (TTL) under timely sown irrigated (TSI) condition wheat genotype NL 1073 produced the grain yield of 3695 kg/ha and under the timely sown rainfed (TSR) that was 2738 kg/ha in 2010/11. In 2011/12, wheat genotype NL 1073 had the highest recorded grain yield of 3691 kg/ha in mid western region which was followed by check variety Vijay in CFFT-TTL in 2011/12 in the same region. Similarly in 2012/13, check variety Vijay showed the highest grain yield of 3818 kg/ha and 3044 kg/ha followed by NL 1094 (2938 kg/ha and 3468 kg/ha) in TSR and TSI environments, respectively. In CFFT for Mid and High Hill (MHH) WK 1204 had the highest grain yield of 3967 kg/ha in TSI which was followed by NL 1008 with the yield of 3890 in 2010/11. In 2011/12 the highest mean grain yield was observed in WK 1204 (4242 kg/ha) followed by BL 3872 (3922 kg/ha). Similarly, in 2012/13 NL 1008 was the best genotypes on the basis of grain yield (3297 kg/ha) followed by NL 1055 (3131 kg/ha) under CFFT-MHH

Variation in grain zinc and iron concentrations, grain yield and associated traits of biofortified bread wheat genotypes in Nepal

Wheat (Triticum aestivum L.) is one of the major staples in Nepal providing the bulk of food calories and at least 30% of Fe and Zn intake and 20% of dietary energy and protein consumption; thus, it is essential to improve its nutritional quality. To select high-yielding genotypes with elevated grain zinc and iron concentration, the sixth, seventh, eighth, and ninth HarvestPlus Yield Trials (HPYTs) were conducted across diverse locations in Nepal for four consecutive years: 2015–16, 2016–17, 2017–18, and 2018–19, using 47 biofortified and 3 non-biofortified CIMMYT-bred, bread wheat genotypes: Baj#1, Kachu#1, and WK1204 (local check). Genotypic and spatial variations were found in agro-morphological traits; grain yield and its components; and the grain zinc and iron concentration of tested genotypes. Grain zinc concentration was highest in Khumaltar and lowest in Kabre. Likewise, grain iron concentration was highest in Doti and lowest in Surkhet. Most of the biofortified genotypes were superior for grain yield and for grain zinc and iron concentration to the non-biofortified checks. Combined analyses across environments showed moderate to high heritability for both Zn (0.48–0.81) and Fe (0.46–0.79) except a low heritability for Fe observed for 7th HPYT (0.15). Grain yield was positively correlated with the number of tillers per m2, while negatively correlated with days to heading and maturity, grain iron, grain weight per spike, and thousand grain weight. The grain zinc and iron concentration were positively correlated, suggesting that the simultaneous improvement of both micronutrients is possible through wheat breeding. Extensive testing of CIMMYT derived high Zn wheat lines in Nepal led to the release of five biofortified wheat varieties in 2020 with superior yield, better disease resistance, and 30–40% increased grain Zn and adaptable to a range of wheat growing regions in the country – from the hotter lowland, or Terai, regions to the dry mid- and high-elevation areas

Phenotypic characterization of wheat landraces from mid and far western districts of Nepal

The study was conducted to evaluate phenotypic variation in one hundred and sixty six wheat landraces from mid and far western districts of Nepal. They were sown in randomized complete block design with two replications at National Wheat Research Program in 2014/15. The observed traits were analyzed using descriptive statistics and multivariate analysis using MINITAB v. 14. The results showed a wide range of phenotypic variability in observed parameters. The results also showed that the highest value of the standard deviation from mean (Sd) was for grain yield (±290.10) followed by plant height (±7.21). Among the traits the lowest deviation from mean (Sd) was for thousand grain weight TGW (±2.68). Wheat landraces grouped in four clusters depending on similarity of the studied traits. The results in this cluster, showed that days to maturity ranged from 97 to111 days, TGW ranged from 16 to17 gm, plant height ranged from 76 to 85 cm, and grain yield ranged from 2800 to 3000 Kg ha-1. Wheat landraces under study are grouped depending on specific traits useful for wheat improvement program. Results of this study can be supportive to detect wheat landraces within species with similar traits. In addition it can be useful for sampling in successive studies and parental selection in wheat breeding program.International Journal of Environment Vol.4(4) 2015: 32-44</p

FIELD BASED ASSESSMENT OF FOLIAR BLIGHTS DISEASE OF WHEAT (Triticum aestivum L.)

  Wheat, the third major staple crop of Nepal has been suffered from many diseases. Various diseases are the major limiting factors of considerable wheat production, one of them is Spot blotch. Spot blotch caused by Bipolaris sorokiniana is a major disease of wheat in warm and humid regions of the Nepal. The fungus has a worldwide distribution but as a pathogen it is the most aggressive under the conditions of high relative humidity and temperature associated with the low fertility of soils in South Asia, South America, Africa, and Australia. The yield loss due to the disease is very significant Nepal. This experiment was conducted to identify the genotypes (crossing) having good level of resistance against spot blotch. The experiment set was received from CIMMYT comprises 52 entries and arranged in alpha lattice design with two replication in 2012/13 at NWRP, Bhairahawa condition. Three times diseases scoring were done in double digit method and calculated the Area under disease progress curve (AUDPC). Heading days, days to maturity, plant height and test weight were found highly significant but the grain yield and AUDPC were not significant among the entries. However, the grain yield and test weight (50.5 gm) were found higher where the AUDPC was lower recorded in genotype 6719 (4046 kg/ha and AUDPC 488.33) followed by genotype 6737 (3765 Kg/ha and AUDPC 576.9) and genotype 6718 (3550 kg/ha and AUDPC 596.33). International Journal of Environment Volume-4, Issue-3, June-August 2015Page: 140-150</p