Background: Improving the productivity of grain legumes is important to address global challenges of food security and soil degradation. This study’s objective was to quantify the adoption of improved mungbean (Vigna radiataL.) varieties and agricultural practices and to identify production constraints for six countries in Southeast Asia and three countries in East Africa.Methods: A Delphi method using expert elicitation was applied at subnational levels and then aggregated to national levels. Each panel employed repetitive and independent questioning of experts. The study organized 31 expert panels involving 387 experts across 9 countries.Results: The share of improved varieties in the planted area, as estimated by the expert panels, was 92% for the Philippines, 91% for Vietnam, 99% for Thailand, 84% for Cambodia, 60% for Indonesia, 35% for Laos, 91% for Kenya, 30% for Uganda and 25% for Tanzania. The average age of improved varieties was 19 years in Asia and 12 years in East Africa. Of the mungbean area in Southeast Asia, 61% was planted to varieties developed by the World Vegetable Center, but this was only 2% in East Africa. Production constraints generally included insect pests and plant diseases, unstable markets with low price and low market demand, and the lack of quality seed of suitable varieties.Conclusions: There are ample opportunities to improve mungbean productivity through wider use of improved varieties and practices, which is important to meet the contemporary challenges of improving human nutrition and agricultural sustainability.

This study analyzes the factors that influence the probability and extent of the adoption of mungbean production technologies in Tanzania, Kenya and Uganda, using multivariate probit and Poisson regression models. The results show that the probability and extent of the adoption of mungbean production technologies are influenced by gender of the household, household size, farm size, livestock size, household assets, access to extension services and access to credit. The study suggests that policy interventions that aimed at targeting women farmers, increasing household asset and information dissemination, such as field demonstrations and training programs, are crucial in enhancing technology adoption among smallholder farmers.

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 ( < 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 ( < 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.

Background: Genome-wide association studies (GWAS) have been utilized to detect genetic variations related to the powdery mildew (PM) resistance and several agronomic traits in common bean. However, its application in common bean and the PM interactions to identify genes and their location in the common bean genome has not been fully addressed.Results: Genome-wide association studies (GWAS) through marker-trait association are useful molecular tools for the identification of disease resistance and other agronomic traits. SNP genotyping with a BeadChip containing 5398 SNPs was used to detect genetic variations related to resistance to PM disease in a panel of 211 genotypes grown under field conditions for two consecutive years. Significant SNPs identified on chromosomes Pv04 and Pv10 were repeatable, confirming the reliability of the phenotypic data scored from the genotypes grown in two locations within two years. A cluster of resistance genes was revealed on the Pv04 of common bean genome among which CNL and TNL like resistance genes were identified. Furthermore, two resistance genes Phavu_010G1320001g and Phavu_010G136800g were also identified on Pv10; further sequence analysis showed that these genes were homologs to the Arabidopsis disease resistance protein (RLM1A-like) and the putative disease resistance protein (At4g11170.1), respectively. Two LRR receptor-like kinases (RLK) were also identified on Pv11 in samples collected in 2018 only. Many genes encoding auxin-responsive protein, TIFY10A protein, growth-regulating factor 5-like, ubiquitin-like protein, cell wall protein RBR3-like protein related to PM resistance were identified nearby significant SNPs. These results suggested that the resistance to PM pathogen involves a network of many genes constitutively co-expressed and may generate several layers of defense barriers or inducible reactions.Conclusion: Our results provide new insights into common bean and PM interactions, and revealed putative resistance genes as well as their location on common bean genome that could be used for marker-assisted selection, functional genomic study approaches to confirm the role of these putative genes; hence, developing common bean resistance lines to the PM disease.

Background: Micronutrient deficiencies caused by lack of Iron (Fe), Zinc (Zn) and Vitamin A have negative effects on human health worldwide. Even though common bean meets Fe and Zn deficiencies based on recommended dietary allowances, the cooking time remains an important challenge. Understanding the genome organization, the loci and genes localization controlling multiple traits is crucial for developing enhanced micronutrient content and improved common bean with short cooking time. Results: In this study, GWAS method was used to determine SNPs associated with four traits studied, including water uptake, cooking time, Fe and Zn concentration level, using ~5,000 SNPs for a panel of 206 genotypes. By the analysis of population structure, 206 common bean genotypes were formed in three groups, the Mesoamerican gene pool, the Andean gene pool, and the admixture gene pool using the Bayesian method. With the significance levels between p = 2.94 x 10^-08 to p = 8.33 x 10^-03 and phenotypic variation of 8.26% to 18.19%, total of 10 SNPs was found to be significantly associated with traits on chromosomes Pv03, Pv04 and Pv10. Among of these SNPs, four SNPs were associated with water uptake, another four SNPs with the cooking time, one SNP with Zn concentration and one of less significant SNP associated with Fe concentration. Within the range or nearby the peak of significant SNP, putative loci encoding pectin degradation, cell structure and cellular exchange/transport were identified, suggesting these loci may play important roles in modulating expression of traits.Conclusion: The resultant data in this study contributed on deciphering the molecular mechanisms associated with water uptake, cooking time and micronutrient contents in common bean. The investigation of association between phenotypic and genotypic data has showed that GWAS approach is a powerful tool to dissect genetic architecture of complex traits and cooperate molecular breeding for advanced genotypes with enhanced micronutrients and short cooking time.