Sets of 280 and 290 bread wheat genotypes were studied for yellow rust (YR) resistance in 2018 and 2019, respectively, at different locations of Nepal. These sets comprised advanced breeding lines, lines in yield trials, varietal candidates and released varieties for irrigated, rainfed and high hills. During 2018, 162 genotypes were resistant to yellow rust and 118 were susceptible at seedling stage at Khumaltar. However, at adult stage only 71 remained resistant whereas 141 beacame moderately resistant. At Dolakha location, only 16 genotypes were resistant whereas 206 were moderately resistant to YR. Majority of the genotypes were resistant in Lumle, Surkhet, Dolakha and Dadeldhura in 2019 under natural epiphytotic condition, however in Khumaltar only few were resistant, and most were moderately resistant under artificial epiphytotic condition. Seedling resistance was evaluated in polyhouse tests, showing mostly resistant reaction to YR pathogen. YR was not observed at Surkhet. At Lumle, two genotypes were moderately resistant. Most of these wheat genotypes were found resistant in Dolakha. Meanwhile in Dadeldhura, 15 were susceptible to yellow rust and most of them were resistant. To find the effective YR resistance genes against the prevailing pathotypes in Kathmandu valley, 19 near-isolines (NILs) were evaluated under natural conditions. In both years, nine Yr genes viz. Yr5, Yr9, Yr10, Yr15, Yr24, Yr26, Yr27, YrSp and Yr18 (Jupateco R) were effective against the prevailing pathotypes of YR fungus, whereas Yr1, Yr6, Yr7, Yr8, Yr17, Yr32 and YrA were ineffective.
