Cowpea (Vigna unguiculata) Landraces and Wild Relatives as Sources of Anthracnose Resistance: Implications for Breeding

Cowpea (Vigna unguiculata (L.) Walp.) is a legume valued in several countries for its nutritional quality, low input requirements, and economic profitability. However, cowpea productivity is significantly constrained by anthracnose disease caused by Colletotrichum species. Enhancing host resistance through the introgression of resistance alleles from landraces and wild relatives offers a promising strategy for durable disease management. This study evaluated 20 cowpea landraces and 18 V. unguiculata ssp. dekindtiana accessions for resistance to anthracnose under natural field infection. The cultivars Ife Brown and V. vexillata line TVNu-428 were included as susceptible and resistant checks, respectively. The experiment was laid in an alpha lattice design (8 × 5) with three replications arranged. Anthracnose symptoms characterized by enlarged light-brown lesions surrounded by reddish-brown halos were produced on all the accessions and the symptoms progressed throughout the assessment period. Five V. unguiculata ssp. dekindtiana accessions (TVNu-113, TVNu-1506, TVNu-1222, TVNu-420, and TVNu-136) and three cowpea landrace accessions (TVu-14076, TVu-17556, and TVu-17567) were identified as promising sources of anthracnose resistance. These accessions represent valuable genetic resources for broadening the cowpea resistance gene pool and support the strategic utilization of wild cowpea germplasm in breeding programs.