Identification and confirmation of trailing-type vegetable cowpea resistance to anthracnose

Anthracnose, caused by Colletotrichum lindemuthianum, is the most destructive disease in cowpea worldwide, leading to complete crop loss with no recommended management strategy. The few resistance sources available belong to the bush type grain cowpea (ssp. cylindrica ) and usage of these lines in resistance breeding invites extensive backcrossing. Recently, from farmers’ fields of Malappuram district of Kerala state in India, a trailing-type vegetable cowpea (ssp. sesquipedalis ), Arimbra Local has been reported to possess resistance to this disease. The present study confirmed the resistance through controlled artificial inoculation and the basis of resistance was analyzed through protein profiling and defense enzyme analyses. Protein profiling has revealed that the resistant varieties are capable to maintain a high level of RuBisCo, the main photosynthetic enzyme, consistently, whereas the susceptible varieties had shown a drastic fall in the level of this enzyme soon after fungal infection. Further, the defense enzymes such as peroxidase and phenylalanine ammonia-lyase were also related to the level of resistance. Hence, Arimbra Local is recommended for the crop improvement programs in trailing-type vegetable cowpea, intended for enhancing the resistance to anthracnose.