Phenotypic and genotypic screening of cowpea germplasm for resistance to bruchid beetle

Abstract:

While cowpea serves as a cheap protein source for millions, storage losses from bruchid beetle (Callosobruchus maculatus F.) routinely destroy 20-40% of harvested grain in warm climates. This research screened 89 cowpea accessions from the Kuban Agricultural University germplasm collection for bruchid resistance using both phenotypic (no-choice bioassay) and genotypic (SSR marker) approaches during 2022-2023 at Krasnodar, Russia. Only 11 accessions (12.4%) qualified as resistant, showing less than 15% seed damage and fewer than 8 adult emergences per 50-seed sample after 60 days of infestation. Forty-four markers were tested; SSR loci VuBr-1 and VuBr-3 on linkage groups 5 and 8 explained 34.7% and 18.3% of the variance in seed damage, respectively. A strong positive correlation (R² = 0.96) linked seed damage to adult emergence. Resistant accessions KU-41, KU-67, and KU-83 are recommended as donor parents for bruchid resistance breeding.