Identification and evaluation of Indian mustard genotypes for white rust resistance and agronomic performance

The screening of 2000 Indian mustard accessions against white rust and phenotypic evaluation of resistant accessions to assess the nature and magnitude of genetic diversity including their agronomic potential was carried out at three locations during rabi of 2014–2016. Out of 2000 germplasm accessions, 168, 46 and 185 accessions were found resistant at Ludhiana, Pantnagar, and Hissar, respectively but only 27 were identified as resistant across the locations indicating the pathogenic variability at different locations. These 27 accessions were further validated under artificial inoculation and eight of them, namely, IC265495, IC313380, EC766091, EC766133, EC766134, EC766192, EC766230 and EC766272 were identified as highly resistant with disease severity reaction (PDI = 0) to A. candida at both cotyledonary and true leaf stages. Agronomic evaluation of these 27 accessions facilitated the identification of superior genotypes with high magnitude of genetic diversity for their use in breeding. As compared to check varieties, elite genotype(s) such as IC313380 was found promising for days to flowering (40), silique on main stem (52.6), silique length (4.2 cm), seeds per silique (17.2) and oil content (41.4%); EC766230 for no. of primary branches (8), seeds/silique (16.8), seed yield/plant (16.0g), oil content (38.7%) while EC766272 for silique on main stem (55.50), seed yield/plant (18g) and oil content (40.5%). The resistant accessions coupled with agronomic superiority may be useful genetic resources for improvement of Indian mustard. In addition, the resistant accessions can serve as a rich gene pool for breeding programmes.