Identification of Cowpea Genotypes with Enhanced Resistance to Callosobruchus maculatus (F.) for Sustainable Storage in Pest Management

Abstract

Callosobruchus maculatus (F.) is a devastating storage pest of cowpea, causing significant
losses if left uncontrolled. This study evaluated the response of 411 cowpea genotypes to
C. maculatus infestation to identify novel sources of resistance and investigate associations between bruchid growth, damage parameters, and resistance metrics. The experiment was conducted at Entomology Laboratory, Department of Zoology, Ahmadu Bello University, Zaria using completely randomized design (CRD). A no-choice assay was employed to screen cowpea genotypes, and data were collected on bruchid growth, damage parameters, and seed morphometric traits. Statistical analysis revealed significant differences (p <0.05) among genotypes for all measured traits, indicating substantial variability for bruchid resistance. Five genotypes (ABU_Vu16, ABU_Vu39, ABU_Vu225, ABU_Vu239, and ABU_Vu309) showed high bruchid tolerance (>70%) and low Dobie susceptibility index (DSI) values (<3). Negative associations were observed between percentage pest tolerance and adult emergence, growth index, and DSI, suggesting that selecting for lower values of these traits can enhance bruchid resistance. Our findings identify reliable indicators of bruchid resistance in cowpea and highlight the potential of these genotypes for developing sustainable storage pest management strategies using a multi-trait approach. This approach is essential, as various factors influence the bruchid resistance trait