EVALUATION OF COWPEA (Vigna unguiculata L.) GENOTYPES FOR RESISTANCE TOANTHRACNOSE DISEASE CAUSED BY Colletotrichum lindemuthianum (Sacc. and Magn.)

Abstract

Anthracnose is a highly detrimental disease in cowpea which causes significant economic impact in cowpea production as well as health related diseases to cowpea consumers worldwide, especially in the sub-Sahara region. The study was conducted to screen twenty cowpea genotypes for resistance to anthracnose disease caused by Colletotrichum lindemuthianum under natural conditions. Under laboratory conditions, seeds from twenty cowpea genotypes were initially examined for the presence of seedborne fungi and their impact on the field emergence of seedlings using the agar plate method. Field experiments were conducted in the 2022 cropping season, employing a randomized complete block design with three replications at two locations in Upper East Region - Ghana. Data on disease incidence and severity were collected. Agronomic and yield parameters, namely emergence percentage, days to 95% pod maturity, plant height at maturity, grain yield, hundred-seed weight, and biomass yield were also assessed. Pathogenicity test was conducted under screen house conditions, involving artificial inoculation on nine genotypes using a fresh culture suspension of C. lindemuthianum in a completely randomized design replicated thrice. Results of both field and screen house experiments revealed significant variations among cowpea genotypes in terms of disease severity and incidence. Anthracnose disease had significant impact on cowpea yield with susceptible genotypes, namely IT17K-2024-4 and IT17K-1367-2-1 displaying comparatively low yield. Based on the findings, two lines from the assessed genotypes, namely IT14K-1424-12 and IT14K-2030-2, exhibited significant resistance to anthracnose disease and demonstrated a high grain yield potential exceeding 2.0 t/ha. These are recommended for release to farmers as part of an integrated disease management approach. However, the most susceptible genotypes such as IT17K-1367-2-1, and IT17K-2024-4, are not recommended for cultivation due to high susceptibility and low yield