Genetic parameters and combined selection for seed coat color and macrominerals in Mesoamerican common bean lines
The development of common bean cultivars with biofortified grains for macrominerals and a seed coat color pattern that satisfies consumer preference is a new demand of breeding programs. However, combined selection for seed coat color and macromineral concentrations in common beans is unprecedented. The objectives of this work were to obtain estimates of genetic parameters for seed coat color and macromineral concentrations in a recombinant inbred line population of Mesoamerican common beans and to select superior common bean lines for a biofortification program. A biparental cross BRS Esteio × SCS 205 Riqueza resulted in 100 Mesoamerican common bean lines that were evaluated in the F5:6 and F5:7 generations. Seed coat color was evaluated in a colorimeter by values L* (white to black), a* (green to red), and b* (blue to yellow). Macromineral concentrations (potassium, calcium, and magnesium) were quantified by nitric‐perchloric acid digestion. A significant treatment effect for all traits evaluated at the F5:6 and F5:7 generations was observed. Seed coat color (L*, a*, and b* values) presented high heritability estimates (h2: 95.99 to 99.72%) and qualitative inheritance. Heritability estimates from intermediate to high magnitude (h2: 34.08 to 99.50%) were obtained for the concentrations of potassium, calcium, and magnesium. Transgressive segregation and quantitative inheritance for the macromineral concentrations were observed in the F5:7 generation. The four superior common bean lines selected by the index were L 83-17, L 69-17, BRS MG Pioneiro, and L 24-17. The lines L 83-17 and L 69-17 of black beans have darker grains (lower L*, a*, and b* values) and high concentrations of potassium, calcium, and magnesium. The lines BRS MG Pioneiro and L 24-17 of carioca beans present lighter grains (L* ≥ 55, a* ≤ 7 and b* ≤ 16), and high mineral concentration. These lines will be selected for a common bean biofortification program.