Mungbean [Vigna radiata (L.) R. Wilczek var. radiata] is an important food and cash legume crop in Asia. Development of short duration varieties has paved the way for the expansion of mungbean into other regions such as Sub-Saharan Africa and South America. Mungbean productivity is constrained by biotic and abiotic factors. Bruchids, whitefly, thrips, stem fly, aphids, and pod borers are the major insect-pests. The major diseases of mungbean are yellow mosaic, anthracnose, powdery mildew, Cercospora leaf spot, halo blight, bacterial leaf spot, and tan spot. Key abiotic stresses affecting mungbean production are drought, waterlogging, salinity, and heat stress. Mungbean breeding has been critical in developing varieties with resistance to biotic and abiotic factors, but there are many constraints still to address that include the precise and accurate identification of resistance source(s) for some of the traits and the traits conferred by multi genes. Latest technologies in phenotyping, genomics, proteomics, and metabolomics could be of great help to understand insect/pathogen-plant, plant-environment interactions and the key components responsible for resistance to biotic and abiotic stresses. This review discusses current biotic and abiotic constraints in mungbean production and the challenges in genetic improvement.

Cowpea (Vigna unguiculata L. Walp) is an important grain legume in most parts of Sub Saharan Africa. However, viral diseases are a major limiting production factor causing significant yield losses. An experiment was conducted to evaluate the reaction of 105 different cowpea genotypes to viral infection in different agro-ecological zones of Uganda. The aim was to identify genotypes that could serve as sources of resistance to virus infection. Virus infection in these experiments occurred naturally through insect vectors. Results showed that there were significant differences in disease reaction among genotypes within and among agro-ecological zones in terms of Area Under Disease Progress Curve (AUDPC) and incidence. Interactions of genotype by season (GXS), genotype by location (GXL) and genotype by location by season (GXLXS) also significantly affected reaction to viral infection among genotypes. Introduced cowpea genotypes exhibited a more susceptible viral disease reaction compared to the landraces over the two seasons in the three locations. A number of landraces such as WC32, WC18, NE43, NE15, WC35B consistently showed resistance to virus infection in the three locations and therefore could be good sources of resistance. Low disease pressure (AUDPC) was also recorded on SECOW2W (released variety) as reported by previous studies. The landraces also gave consistently higher grain yield values compared to the introduced genotypes. Overall, data from this study showed that locally adapted cowpea genotypes offer resistance to virus infection and may be desirable germplasm for Ugandan cowpea breeding programs.

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 radiata L.) 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.

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Cowpea (Vigna unguiculata) is one of the important legume crops in Uganda especially in the eastern and northern regions. Its productivity in the country is, however, still low. Environmental constraints and occurrence of genotype × environment interactions (G × E) contribute greatly to the low production. In this study, an additive main effects and multiplicative interaction analysis (AMMI) model was used to assess the yield stability of 30 cowpea genotypes planted in five locations for three consecutive seasons. Also, the relationship of G × E interaction with genotypic/weather variables was analysed. AMMI analysis of variance indicated that environment had the highest contribution to the variation in grain yield. Postdictive success method indicated AMM1-3 as the best model since the first three interaction principal component axes (PCA1, PCA2, PCA3) were significant (p = 0.0000). Together, the first three PCAs explained 75.1% of the G × E interaction sum of squares. However, according to the predictive success method, AMMI-1 was the best model. The AMMI stability value (ASV) identified five genotypes; UCR 5279, Ayiyi, IT07K-257-33, ACC122*WC66 and IT06K-281-1 as being more stable. These ABOUT THE AUTHORS Mbeyagala, E. K (PhD) is a Senior Scientist (Legume breeding) working for the National Agricultural Research Organization (NARO) based at the National Semi-Arid Resources Research Institute (NaSARRI). He is currently the leader of the National Dryland Legume Research Program and also heads cowpea, mungbean and pigeonpea breeding activities in Uganda. His research focuses on developing varieties with tolerance/resistance to biotic/abiotic stresses and with acceptable farmer/consumer traits. Ariko, J.

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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.

Greengram, Vigna radiata (L.) Wilczek is an important source of proteins and micronutrients to small holder farmers in eastern and northern regions of Uganda. Most of the landraces currently grown by small scale farmers are characterized by low yields and late maturity. In order to identify high yielding and stable varieties, an experiment was conducted to evaluate the yield performance of introduced early maturing genotypes from the World Vegetable Centre (AVDRC) in seven locations of Uganda. Yield performance data for the genotypes was subjected to analysis of variance (ANOVA) to test the significance of genotype × environmental interactions as well as stability analysis using the yield -stability statistic (YS i ) as an aid for simultaneous selection for high yield and stability. Analyses of variance showed that genotype × environmental interactions (G×E) were significant and therefore could not be ignored. Following the detection of significant genotype × environmental interactions, yield -stability statistics (YS i ) were generated and used for simultaneous selection for high yield and stability among the introduced genotypes. Yield-stability statistics (YS i ), indicated that three introduced genotypes (Filsan, Sunshine, and Blackgram) in addition to the local check were stable and high yielding. These genotypes need to be assessed for farmer preferences/tastes and other quality traits in on-farm participatory trials before they can be recommended for release.