Yield and Mineral Composition among Mungbean [Vigna radiata (L.) R. Wilczek] Genotypes Grown in Different Agroecologies in East Africa

Mungbean [Vigna radiata (L.) R. Wilczek var. radiata] also referred to as green gram is a key crop especially in the marginal areas of East Africa. It is rich in micronutrients and protein and thus can help ameliorate malnutrition if incorporated into diets. This study was conducted to evaluate the performance of 26 fixed elite mungbean breeding genotypes for yield and micronutrient composition across different locations in East Africa (Uganda, Kenya, and Tanzania). The genotypes displayed significant variability for nutritional, phenology, and yield-related traits across test environments. Significant genotype effects were observed for most of the traits except for average yield per plant and dry matter content (P < 0.05). Random effect of environment was significant for all traits, and significant GXE was observed for all traits except for dry matter and iron content (P < 0.05). Moderate to high broad-sense heritability (H2) was found among traits except for dry matter content which was low (H2 = 10.4%). There was a significant and positive correlation between Fe and Zn (r = 0.58), and Fe and Ca (r = 0.46), indicating the potential to enhance these traits simultaneously through breeding and/or selection. However, the correlation between yield and nutrients (iron, zinc, and calcium) was negative. Environments KAT_SR_2019, KYM_LR_2020, and KYM_LR_2020 were found to be discriminating (informative) and representative of grain yield, calcium, and zinc content, respectively. Genotypes AVMU 1679, AVMU 1685, and AVMU1686 combined both stability and high micronutrient content, while the high yielding and stable genotypes were AVMU 1689, AVMU 1681, and AVMU 16102. The identified genotypes need to be assessed for farmer preference in on-farm trials before they can be recommended for release as new varieties. Additionally, these genotypes will be useful in future breeding efforts as donors aimed at developing nutrient-dense and high yielding mungbean varieties.