Rice blast caused by Pyricularia grisea Sacc. is the important disease of rice and different fungicides against this disease were evaluated in summer 2014 at Karma Research and Development Center, Jyotinagar, Chitwan, Nepal. A susceptible rice cultivar ‘Mansuli’ was planted in randomized complete block design and fungicides viz. Tricyclazole  22% + Hexaconazole 3% SC (0.2%), Streptomycin 5% + Thiophanate Methyl 50% WP (0.15%), Prochloraz 25% EC (0.3%), Kasugamycin 2% WP (0.2%), Hexaconazole 4% + Zineb 68 % WP (0.2%) and Udaan (Hexaconazole 3% SC) (0.2%) were sprayed thrice at weekly interval starting from the booting stage. All these fungicides were found to be effective in controlling leaf and neck blast disease as compare to control one. Among them, Tricyclazole 22% + Hexaconazole 3% SC was found to be the most effective with least leaf blast severity (6.23%), neck blast incidence (8.97%), and highest percentage disease control (87.08% and 79.62% in leaf blast and neck blast respectively) and grain yield (4.23 t/ha) followed by Prochloraz 25% EC (0.3%) and Udaan (Hexaconazole 3% SC) (0.2%). It is therefore concluded that Tricyclazole 22% + Hexaconazole 3% SC fungicide could be used to control rice blast at weekly interval starting from the booting stage for three times. Int J Appl Sci Biotechnol, Vol 3(3): 474-478

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A field experiment was conducted on fourteen rice varieties to determine the level of resistance against brown leaf spot (Bipolaris oryzae)disease at Karma Research and Development Center, Jyotinagar, Chitwan during summer in 2013. Design used was randomized completeblock design with three replications. Disease severity, total AUDPC value, thousand grain weight and grain yield were highly significant amongthe rice varieties. Disease severity and total AUDPC value ranged from 21.73% to 58.07% and 614.8 to 1827 respectively. None of thesevarieties were found either resistant or highly resistant to disease. Only HJ-G1 and HJ-G2 were moderately resistant with grain yield of 5.10t/ha and 4.25 t/ha respectively. HJ-G1 variety had the highest grain yield 5.10 t/ha and lowest disease severity (21.73%) as well as total AUDPCvalue (6148). From this experiment, it can be concluded that HJ-G1 variety can be used for higher grain yield purpose under similar fieldcondition because it has highest yield and also tolerant to disease.DOI: http://dx.doi.org/10.3126/ijasbt.v3i1.12014   Int J Appl Sci Biotechnol, Vol. 3(1): 56-60

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 dryer mid- and high-elevation areas.

Fusarium wilt of banana (FWB), caused by Fusarium oxysporum f. sp. cubense (Foc), is the most important constraint of the banana industry globally. In Nepal, epidemics resembling FWB have been increasingly observed on the Malbhog cultivar in the past several years. However, the disease has not been officially reported yet, and consequently, little is known about the pathogen present across the country. In this study, we characterized 13 fungal strains isolated from banana plants of the Malbhog cultivar (Silk, AAB) showing symptoms similar to FWB in banana plantations in Nepal. All of the strains were typed as belonging to the F. oxysporum and caused FWB symptoms when inoculated in the Malbhog and Cachaco (Bluggoe, ABB) cultivars. No symptoms were observed in the Williams cultivar (Cavendish, AAA). Vegetative compatibility group (VCG) analysis classified the strains as VCG 0124 or VCG 0125. PCR analyses conducted with primers specific for Foc race 1 (Foc R1) or Foc tropical race 4 (TR4) revealed that all the strains reacted positively for Foc R1 and none for TR4. Altogether, our results demonstrated that the pathogen populations causing FWB of the Malbhog cultivar in Nepal were Foc R1. This work reported, for the first time, the occurrence of FWB in Nepal. Further studies with larger Foc populations are needed to better understand disease epidemiology to design sustainable disease management strategies.