Screening of Rapeseed–Mustard Genotypes for Resistance to Alternaria Leaf Blight Disease Under Natural and Artificially Inoculated Conditions

Abstract

Rapeseed–mustard (Brassica spp.) is a major oilseed crop in India and plays a vital role in edible oil production. However, its productivity is severely constrained by Alternaria leaf blight, caused predominantly by Alternaria brassicae. The disease leads to premature defoliation, poor seed filling, and shriveled grains, resulting in yield losses ranging from 35–50% under severe natural conditions. The present study was conducted to evaluate the resistance of diverse rapeseed–mustard genotypes against Alternaria leaf blight under both natural field conditions and standardized artificial inoculation. A set of 48 genotypes, including susceptible checks, was screened. Under natural conditions, 7 genotypes showed susceptible, 41 genotypes moderate susceptible, whereas no any genotypes showed immune, resistance, moderate resistance and highly susceptible. Under artificially inoculated conditions, 22 genotypes showed susceptible, 26 genotypes moderately susceptible, whereas no any genotypes showed immune, resistance, moderate resistance and highly susceptible.