Phenotype based clustering, and diversity of common bean genotypes in seed iron concentration and cooking time

Authors: AMONGI, WINNYFRED - Makerere University; NKALUBO, STANLEY - National Crops Resources Research Institute; OCHWO-SSEMAKULA, MILDRED - Alliance Of Bioversity International And The International Center For Tropical Agriculture (CIAT); ARFANG, BADJI - National Crops Resources Research Institute; DRAMADRI ONZIGA, ISAAC - Makerere University; ODONGO LAPAKA, THOMAS - Makerere University; NUWAMANYA, EPHRAIM - Makerere University; TUKAMUHABWE, PHINEAS - Makerere University; IZQUIRDO, PAULO - Michigan State University; Cichy, Karen; KELLY, JAMES - Michigan State University; MUKANKUSI, CLARE - Alliance Of Bioversity International And The International Center For Tropical Agriculture (CIAT)

Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/12/2023
Publication Date: 5/11/2023
Citation: Amongi, W., Nkalubo, S., Ochwo-Ssemakula, M., Arfang, B., Dramadri Onziga, I., Odongo Lapaka, T., Nuwamanya, E., Tukamuhabwe, P., Izquierdo, P., Cichy, K.A., Kelly, J., Mukankusi, C. 2023. Phenotype based clustering, and diversity of common bean genotypes in seed iron concentration and cooking time. PLOS ONE. 18(5). Article e0248976. https://doi.org/10.1371/journal.pone.0284976.
DOI: https://doi.org/10.1371/journal.pone.0284976

Interpretive Summary: Common bean is an important grain legume crop of global importance, especially for human consumption. The crop provides calories, protein, and micronutrients, notably iron, zinc, thiamin, and folic acid. Over 400 million people in Africa directly consume common bean. However, because of several biotic and abiotic production challenges, farmer yields in most African is still significantly below the potential yield. Challenges such as long cooking time, and bioactive compounds that influence the bioavailability of iron also affect the consumption and health benefits. The goal of this study was to evaluate the genetic diversity of breeding lines and released varieties in East Africa to inform breeding decisions for resilient fast cooking and iron biofortified in the Pan African Bean Research Alliance (PABRA). In total 427 breeding lines, varieties, or landraces mostly from Uganda and South America were evaluated for days to flowering and maturity, yield, seed iron, zinc, and cooking time. The genotypes exhibited high genetic diversity for seed iron and cooking times and some were identified with value to be used for dry bean genetic improvement.

Technical Abstract: Common bean is the world’s most important directly consumed legume food crop that is popular for calories, protein and micronutrients. It is a staple food in sub-Saharan Africa, and a significant source of iron for anemic people. However, several pests, soil and weather challenges still impede its production. Long cooking time, and high phytic acid and polyphenols that influence bioavailable iron also limit the health benefits. To inform population improvement strategies and selection decisions for resilient fast cooking and iron biofortified beans, the study determined diversity and population structure within 427 breeding lines, varieties, or landraces mostly from Alliance Uganda and Columbia. The genotypes were evaluated for days to flowering and physiological maturity, yield, seed iron (FESEED) and zinc (ZNSEED) and cooking time (COOKT). Data for all traits showed significant (P=0.001) differences among the genotypes. Repeatability was moderate to high for most traits. Performance ranged from 52 to 87 ppm (FESEED), 23–38 ppm (ZNSEED), 36–361 minutes (COOKT), and 397–1299 kg/ha (yield). Minimal differences existed between the gene pools in the mean performance except in yield, where Mesoamerican beans were better by 117 kg/ha. The genotypes exhibited high genetic diversity and thus have a high potential for use in plant breeding. Improvement of FESEED and ZNSEED, COOKT and yield performance within some markets such as red and small white beans is possible. Hybridization across market classes especially for yellow beans is essential but this could be avoided by adding other elite lines to the population. Superior yielding and fast cooking, yellow and large white beans were specifically lacking. Adding Fe dense elite lines to the population is also recommended. The population was clustered into three groups that could be considered for specific breeding targets based on trait correlations.