Biochemical characteristics imparting resistance against Alternaria blight in cauliflower genotypes

Alternaria blight disease has been reported from all the continents of the world, affects most of the cruciferous crops. Alternaria blight incited by foliar pathogen, Alternaria brassicae has become a major constraint in the successful cultivation of this crop. Development of resistant varieties is the most appropriate approach to control the disease and the concept is now developing to explore the built-in plant defense mechanism in relation to pathogen attack. In the present study, an attempt was made to identify biochemical characteristics imparting resistance against Alternaria blight in cauliflower genotypes. The moderately resistant genotypes had higher total chlorophyll, total phenols, total soluble sugars, total proteins, flavonoids and ascorbic acid than the susceptible genotypes. The chlorophyll content was found to be lesser in the infected leaves than the healthy ones. The reduction in total phenols, total soluble sugars, total proteins, flavonoids and ascorbic acid was at a higher rate in susceptible ones than the moderately resistant genotypes. These biochemical characteristics might be responsible for imparting resistance against Alternaria blight in cauliflower genotypes.