Differential reaction of cowpea genotypes to brown blotch disease (Colletotrichum capsici) in Burkina Faso

Thirty six Colletotrichum capsici (L.) single spore isolates associated with brown blotch disease in cowpea were collected from three agro-ecological zones of Burkina Faso from October to November 2014. To identify the most virulent strains, cowpea genotypes KVx61-1, KVx396-4-5-2-D and Moussa Local was inoculated with each isolate. The results showed that isolates 096-SA-2, 071-FA-6 and 079-PM-2 were the most virulent, respectively, in North Soudanian, Soudanian and Sahelian zones. To identify brown blotch disease resistant cowpea, each of the isolates was used to inoculate 41 different cowpea genotypes. Inoculated cowpea plants were evaluated for brown blotch disease severity at 7, 14 and 21 days after inoculation. Highly significant differences (P < 0.001) were found among genotypes, isolates and their interactions. Seven cowpea genotypes including KN-1, Moussa Local, Donsin Local and Melakh were identified as resistant and present specific resistance to the isolates. These genotypes can be used to improve cowpea resistance to brown blotch disease in Burkina Faso. Key words: Cultivars, pathotypes aggressiveness, disease resistance.