Investigation of genotype by environment interactions for seed zinc and iron concentration and iron bioavailability in common bean

Authors: Katuuramu, Dennis; Wiesinger, Jason; LUYIMA, GABRIEL - National Crops Resources Research Institute; NKALUBO, STANLEY - National Crops Resources Research Institute; Glahn, Raymond; Cichy, Karen

Submitted to: Frontiers in Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/24/2021
Publication Date: 5/10/2021
Citation: Katuuramu, D.N., Wiesinger, J.A., Luyima, G.B., Nkalubo, S.T., Glahn, R.P., Cichy, K.A. 2021. Investigation of genotype by environment interactions for seed zinc and iron concentration and iron bioavailability in common bean. Frontiers in Plant Science. 12:670965. https://doi.org/10.3389/fpls.2021.670965.
DOI: https://doi.org/10.3389/fpls.2021.670965

Interpretive Summary: Iron (Fe) and zinc (Zn) malnutrition afflicts millions of people around the world. Iron and Zn are the essential trace minerals deficient in diets of people living in low- and middle- income countries with heavy consumption of plant based staple diets. Common bean (Phaseolus vulgaris L.) is a widely grown and consumed legume crop by millions of people around the world especially in Latin America and Sub-Saharan Africa including Uganda. It is a major source of protein, micronutrients (Zn and Fe), dietary fiber, and vitamins. The presence of wide variability for seed Zn and Fe along with high levels of consumption has made the crop a strong target for biofortification programs in Eastern Africa. Common bean nutrition breeding goals have mainly focused on development and release of genotypes with high levels of Fe. For Fe and Zn biofortified crops to be effective in alleviating deficiency, the minerals must be available for absorption. Iron bioavailability, or the ability for Fe present in the food to be released following ingestion and digestion for absorption and biological functioning of the human body should be an integral process of the common bean biofortification breeding process. This study was conducted to assess the magnitude of genotype and genotype by environment interactions for seed Zn and Fe concentration and iron bioavailability of common bean accessions grown at nine on-farm locations in Uganda. The Manteca yellow bean was found to hold promise for iron nutrition since it combined high iron concentration with high Fe bioavailability in a market class many consumers in Uganda already prefer.

Technical Abstract: Iron and zinc malnutrition are global public health concerns afflicting mostly infants, children, and women in low-income and middle-income countries with widespread consumption of plant based diets. Common bean is a widely consumed staple crop around the world and is an excellent source of proteins, fiber, and minerals including iron and zinc. Development of nutrient dense common bean varieties that deliver more bioavailable iron and zinc with a high level of trait stability requires measurement of the contributions from genotype, environment, and genotype by environment interactions. In this research, we investigated the magnitude of genotype by environment interaction for seed zinc and iron concentration and seed iron bioavailability using a set of nine test genotypes and three farmers’ local check varieties. The research germplasm was evaluated for two field seasons across nine on-farm locations in three agro-ecological zones in Uganda. Seed zinc concentration ranged from 18.0 to 42.0 µg g-1 and was largely controlled by genotype, location, and the interaction between location and season (28.0, 26.2, and 14.7% of Phenotypic Variability Explained [PVE] respectively). Within a genotype, zinc concentration ranged on average 12 µg g-1 across environments. Seed iron concentration varied from 40.7 to 96.7 µg g-1 and was largely controlled by genotype, location, and the interaction between genotype, location, and season (25.7, 17.4, and 13.7% of PVE respectively). Within a genotype, iron concentration ranged on average 28 µg g-1 across environments. Seed iron bioavailability ranged from 8 to 116 % of Merlin navy control and was largely controlled by genotype (68.3% of PVE). The red mottled genotypes (Rozi Koko and Chijar) accumulated the most seed zinc and iron concentration while the yellow (Ervilha and Cebo Cela) and white (Blanco Fanesquero) genotypes had the highest seed iron bioavailability and performed better than the three farmers’ local check genotypes (NABE-4, NABE-15, and Masindi yellow). The genotypes with superior and stable trait performance, especially the Manteca seed class which combine high iron and zinc concentration with high iron bioavailability would serve as valuable parental materials for crop improvement breeding programs aimed at enhancing the nutritional value of the common bean.