Cooking time, seed darkening, and iron and zinc concentrations of selected andean genotypes of common bean

Authors: HAMABWE, SWIVIA - University Of Zambia; KUWABO, KUWABO - University Of Zambia; URREA, CARLOS - University Of Zambia; Cichy, Karen; KAMFWA, KELVIN - University Of Zambia

Submitted to: Legume Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/3/2024
Publication Date: 10/20/2024
Citation: Hamabwe, S., Kuwabo, K., Urrea, C., Cichy, K.A., Kamfwa, K. 2024. Cooking time, seed darkening, and iron and zinc concentrations of selected andean genotypes of common bean. Legume Science. 6(4). Article e70012. https://doi.org/10.1002/leg3.70012.
DOI: https://doi.org/10.1002/leg3.70012

Interpretive Summary: Common bean is a major source of protein and essential minerals iron and zinc for households in Zambia. Purple-mottled and yellow are important market classes in Zambia, however despite their popularity there are currently no improved varieties grown by farmers. Major bean attributes valued by farmers and consumers in Zambia include seed coat color that do not darken with ageing (i.e. post-harvest darkening), short cooking time, and iron nutritional value. There is currently lack of knowledge on the extent of genetic variability for these attributes within Zambian bean germplasm. Such knowledge would support breeding efforts to develop faster cooking varieties that are rich in iron and zinc to benefit Zambian common bean consumers. The objective of this study was to evaluate 52 bean lines for cooking time, post-harvest darkening, seed iron and zinc concentration. Significant variability in cooking time, post-harvest darkening ,and iron and zinc content was observed, with yellow beans having the shortest cooking times on average. Germplasm identified in the study with favorable cooking time, mineral concentrations, and lack of seed coat darkening will be used to breed improved cultivars for Zambia.

Technical 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, post-harvest darkening, seed iron and zinc concentration. A total of 52 genotypes belonging to three market classes, namely purple-mottled (Kabulangeti), yellows and cranberry (sugar beans) were grown at Golden Valley Agricultural Research Trust (GART) Farm in Zambia, and assessed for CT and darkening. Of the 52 genotypes, a subset (22) was grown at GART and Mpika Research Station, and evaluated for 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 while yellows showed slow darkening. The yellow genotype Y1612-3 was particularly outstanding because of unique combination of high concentration of both iron and zinc, and can be used for introgression of these two essential minerals in variable genetic backgrounds. The significant variability and the high to moderate heritability for CT, iron and zinc concentration observed in the current study suggests that it is possible to make progress in breeding faster cooking varieties that are rich in iron and zinc.