Potential of certain cultivars and resistance inducers to control gray mould (Botrytis cinerea) of pepper (Capsicum annuum L.)

Four different highly economic value pepper cultivars Trezaa, Emberu, Mazurka and Taranto usually grown in Egypt were used to evaluate the efficacy of certain resistance inducers to enhance resistance of pepper fruits against gray mould fungus. Pathogenicity tests with Botrytis cinerea (BC-3 isolate) revealed that cv. Mazurka (Red Colour) was most tolerant and exhibited 40.15% rot severity, while cv. Emberu (Yellow Colour) was highly susceptible and showed 79.12% rot severity. The other two pepper cultivars, that is, cv. Trezaa and Taranto showed severity of 50.23 and 52.75%, respectively. Treatment of pepper fruits with resistance inducers salicylic acid (SA); abscisic acid, methyl jasmonate and calcium chloride significantly decreased gray mould development under laboratory conditions. Calcium chloride was the most effective on all pepper cvs. mentioned earlier and inhibited diameter of rotting area with overmean of 40.6%. This was followed by SA as 34.01%. Abscisic acid and methyl jasmonate, however, showed lower mean inhibition of 16.8 and 18.8%, respectively. Meantime, treatment of pepper fruits with such resistance inducers and calcium chloride increased activity of the defense related enzymes, that is, polyphenol oxidase (PPO), peroxidase (POD), phenylalanine ammonia lyase (PAL) as well as the total phenols where SA and calcium chloride were the most effective. This could explain potentiality of such compounds to enhance pepper resistance to control B. cinerea of the gray mould of pepper.