Early-maturing, high-yielding M5 mutant lines of cowpea (Vigna unguiculata) derived from gamma irradiation exhibit enhanced seed protein and mineral composition: implications for nutritional biofortification.

PURPOSE: Cowpea (Vigna unguiculata (L.) Walp.) is the primary grain legume in sub-Saharan Africa, yet protein-energy malnutrition and micronutrient deficiencies persist widely across the region. This study evaluates the proximate and mineral composition of twelve early-maturing, high-yielding M5 mutant lines derived through multi-generational pedigree selection from 60Co gamma irradiation (452 Gy) of the Ghanaian cowpea cultivar Hansadua. MATERIALS AND METHODS: Seeds harvested from a randomized complete block design (three replications) at the University of Cape Coast, Ghana, were analyzed for proximate composition (protein, fat, fiber, ash, carbohydrate, moisture) and mineral content (N, Ca, Na, K, Mg, Fe) using AOAC and wet acid digestion methods. RESULTS: All twelve parameters differed significantly (p < .001) among genotypes. Crude protein ranged from 18.96 ± 0.09% to 30.49 ± 0.14%, compared to 20.54 ± 0.09% in the parent; ten of twelve mutant lines exceeded Hansadua. All mutant lines surpassed the parent in calcium (44.47-105.60 mg/100 g) and potassium (745.87-1,112.03 mg/100 g). Protein was strongly correlated with nitrogen (r = 0.99, p < .001) and magnesium (r = 0.60, p < .001) but was independent of iron (r = 0.18, p > .05). CONCLUSION: Mutant lines HanM4(12)(3), HanM4(52)HY, and HanM4(33)(HY43) show promise for cowpea biofortification breeding efforts aimed at fighting protein-energy malnutrition and mineral deficiencies in West Africa.