Biochemical responses of Cotton genotypes to Alternaria leaf spot disease (Alternaria macrospora Zimm.)

Biochemical studies were carried out on non-Bt, Bt and wild cotton genotypes. Biochemical investigations using resistant, moderately resistant and susceptible genotypes indicated that the content of total sugars, reducing sugars, non reducing sugars, chlorophyll a, chlorophyll b and total chlorophyll content were higher in resistant as compared to susceptible genotypes at both the stages i.e. healthy and infected conditions. Further, the decrease in total sugars, reducing sugars, non reducing sugars, chlorophyll a, chlorophyll b and total chlorophyll content were observed in infected plants. The decrease in biochemical constitutes were comparatively higher in susceptible genotypes. The content of sugars and chlorophyll was found maximum in resistant genotypes at both growth stages (50 & 100 DAS) of cotton.