Cooking Time, Seed Darkening, and Iron and Zinc Concentrations of Selected Andean Genotypes of Common Bean

Abstract

Cooking time (CT), post-harvest darkening (PHD), and micronutrient content influence consumer preference of common bean (Phaseolus vulgaris L.) varieties. The objective of this study was to evaluate Andean genotypes for CT, PHD, and seed iron and zinc concentration. A total of 52 genotypes belonging to three market classes, namely, purple-speckled (Kabulangeti), yellows, and cranberry (sugar beans), were grown at the Golden Valley Agricultural Research Trust (GART) Farm and the Mpika Research Farm in Zambia and assessed for CT, PHD, and seed iron and zinc concentration. The fastest cooking genotype among all 52 genotypes was a yellow genotype, Y1612-5. Yellow genotypes generally cooked faster than the Kabulangeti and sugar types. Among the elite lines with Kabulangeti seed types, which is a dominant market class in Zambia, the elite line K175 had faster CT and higher iron and zinc concentration than the Kabulangeti landrace race currently available on the Zambian market. Kabulangeti and sugar genotypes showed regular darkening, whereas yellows did not darken. The yellow genotype Y1612-3 was particularly outstanding because of its unique combination of high concentrations of both iron and zinc. Therefore, it can be used to introgress these two essential minerals into variable genetic backgrounds. The significant variability and high to moderate heritability for CT (0.85) and iron (0.81) and zinc (0.58) concentration observed in the current study suggest that it is possible to make progress in breeding for faster cooking varieties that are rich in iron and zinc.