Biochemical defence reactions of black pepper varieties against Colletotrichum gloeosporioides incitant of anthracnose disease

Abstract: Anthracnose caused by Colletotrichum gloeosporioides in Black pepper is a severe disease that causes even up to 100 percent crop losses under epidemic conditions. Most of the cultivated varieties of black pepper are highly susceptible to the disease, especially Panniyur 1, the most predominant variety grown in the country. Our study tested 11 black pepper genotypes for their biochemical defense reaction to anthracnose disease. Field observations were initially recorded for two consecutive years in alternate germplasm sites, and the disease incidence ranged between 4.00 and 21.33. The disease incidence under glasshouse conditions upon challenge inoculation was minimal for the variety IISR Girimunda. Upon inoculation with C. gloeosporioides, resistant cultivars exhibited significantly higher activity levels of antioxidant enzymes such as peroxidase, polyphenol oxidase, catalase, phenylalanine ammonia-lyase, and superoxide dismutase compared to local check and uninoculated control plants. This suggests that the variety IISR Girimunda’s resistance to anthracnose may be attributed to its possession of robust biochemical defense molecules.