Mungbean (Vigna radiata (L.) Wilczek), also known as greengram, is the most widely cultivated Asian Vigna species. Improved mungbean cultivars have a narrow genetic base that limits yield potential and they are poorly adapted to varying growth conditions in different agro-ecological conditions. The genetic potential of landrace germplasm accessions in gene- banks therefore needs to be better exploited. Germplasm core collections are made of a reduced set of representative accessions from the entire diversity maintained by genebanks. This subset of accessions can be used for testing general combining ability with local germplasm in the search for yield enhancement. Core collections also help breeders in selecting parental material that could maximize potential genetic gain from derived hybrid populations. At the National Bureau of Plant Genetic Resources (NBPGR), India, genetic enhancement/pre- breeding studies in mungbean have been initiated involving diverse parents mainly from the cultivated gene pool, using the Bureau's core collection as starting material. Germplasm enhancement aims at widening the genetic base of breeding materials by transferring desired genes from unimproved germplasm into enhanced varieties. Mild and decentralized selected material was maintained in target sites across the country. A total of 102 progenies were advanced to F5 for further selection and use by the breeders in Delhi. The genetic potential of a few selected enhanced progenies with desired plant types and better yield-related traits is presented in this paper. The study clearly demonstrates the potential of germplasm accessions conserved in genebanks for use in large-scale base-broadening efforts in mungbean.

Glyphosate-tolerant and glyphosate-resistant weeds are becoming increasingly problematic in cotton fields in Australia, necessitating a return from a glyphosate dominated system to a more integrated approach to weed management. The development of an integrated weed management system can be facilitated by identifying the critical period for weed control (CPWC), a model that enables cotton growers to optimize the timing of their weed control inputs. Using data from field studies conducted from 2003 to 2015, CPWC models using extended functions, including weed biomass in the relationships, were developed for the mimic weeds, common sunflower and Japanese millet, in high-yielding, fully irrigated cotton. A multispecies CPWC model was developed after combining these data sets with data for mungbean in irrigated cotton, using weed height and weed biomass as descriptors in the models. Comparison of observed and predicted relative cotton-lint yields from the multispecies CPWC model demonstrated that the model reasonably described the competition from these three very different mimic weeds, opening the possibility for cotton growers to use a multispecies CPWC model in their production systems.

Research using the critical period for weed control (CPWC) has shown that high-yielding cotton crops are very sensitive to competition from grasses and large broadleaf weeds, but the CPWC has not been defined for smaller broadleaf weeds in Australian cotton. Field studies were conducted over five seasons from 2003 to 2015 to determine the CPWC for smaller broadleaf weeds, using mungbean as a mimic weed. Mungbean was planted at densities of 1, 3, 6, 15, 30, and 60 plants m−2 with or after cotton emergence and added and removed at approximately 0, 150, 300, 450, 600, 750, and 900 degree days of crop growth (GDD). Mungbean competed strongly with cotton, with season-long interference; 60 mungbean plants m−2 resulted in an 84% reduction in cotton yield. A dynamic CPWC function was developed for densities of 1 to 60 mungbean plants m−2 using extended Gompertz and exponential curves including weed density as a covariate. Using a 1% yield-loss threshold, the CPWC defined by these curves extended for the full growing season of the crop at all weed densities. The minimum yield loss from a single weed control input was 35% at the highest weed density of 60 mungbean plants m−2. The relationship for the critical time of weed removal was further improved by substituting weed biomass for weed density in the relationship.

Mungbean seeds, despite being protected inside the pod, are susceptible to pre-harvest sprouting (PHS) following rainfall due to lack of fresh seed dormancy (FSD), which deteriorates the quality of the seed/grain produced. Therefore, development of mungbean cultivars with short (10–15 days) period of FSD has become important to curtail losses incurred by PHS. In this study, we investigated variations in PHS, fresh seed germination (FSG) and activity of α-amylase enzyme in diverse mungbean genotypes. There was a wide variation in PHS tolerance and FSG among 163 genotypes examined and 14 genotypes were found to be tolerant (<20%) to PHS. Seed germination in a pod, a measure used to evaluate PHS, varied from 7.14% in germplasm accession Chamu 4 to 82.52% in cultivated variety IPM 2–3. There was a marked increase in α-amylase activity in genotypes showing high FSG and PHS, especially at 48 and 72 h after germination as compared with PHS tolerant genotypes. Therefore, α-amylase can be used as an effective biochemical marker to evaluate a large number of mungbean genotypes for FSD and PHS. Also, the variation in seed germinability as found in this study could be further used for mungbean improvement programme.

Despite widespread mungbean [Vigna radiata (L.) Wilczek] consumption in Indonesia, few molecular studies have been carried out on accessions and available data are minimal. In this study, we used 30 newly developed simple sequence repeat (SSR) markers designed from the mapped sequence scaffolds of the Korean Sunhwanokdu and Gyeonggijaerae 5 mungbean genomes. These markers were used to examine loci in 83 mungbean accessions collected from diverse geographical areas in Indonesia. A total of 107 alleles were detected among the accessions with 29 polymorphic markers. However, the mean of polymorphic information content (0.33) value and diversity index (0.38) value was indicative of low genetic diversity in this germplasm. The mungbean population structure was not clearly differentiated and the number of subpopulations was unclear. Neighbour-joining tree analysis revealed that the genetic cluster did not reflect the geographical origin of the accessions. Interestingly, the most agriculturally improved varieties were genetically similar to some landraces from one of the main mungbean-producing regions. These newly developed SSR markers could be useful for detecting genetic variability as a basis for establishing a conservation strategy for mungbean germplasm with the aim of enhancing Indonesian breeding programmes.

On the premise that seed ageing may be largely a result of free-radical lipid autoxidation, a study was made of the relationship between lipid stability and longevity in seeds of soybean (Glycine max), lentil (Lens culinaris), mungbean (Vigna radiata), chickpea (Cicer arietinum), broadbean (Vicia faba), pea (Pisum sativum), lettuce (Lactuca sativa), and tomato (Lycopersicon esculentum). Seed lipids were examined for α-, γ- and δ-tocopherols, and levels of unsaturated and saturated fatty acids. Using this information, analysis was attempted using linear, multiplicative or exponential models to correlate aspects of lipid stability with seed longevity values from the published literature. No statistically significant correlations could be found between longevity and total lipid unsaturation, tocopherol levels or two protection formulae obtained from the oil chemistry literature. When values for tomato were excluded, a good correlation (r = 0.89, P = 0.007) was obtained using a multiplicative regression model for levels of linolenic acid per unit of total tocopherols in relation to longevity. Possible factors contributing to a lessening of the relationship between lipid stability and seed longevity are discussed.

Mungbean seeds are often attacked by bruchid insects causing serious damage to the grain during storage. The susceptible/resistant characteristics of mungbean against bruchids have been investigated at the protein level. Seeds of the susceptible cultivar Osaka-ryokuto and the resistant near-isogenic line BC20 were collected at 5, 9, 13, 17, 21 and 23 days after flowering. Crude, cytosol and membrane protein fractions were extracted from the seeds for twodimensional polyacrylamide gel electrophoresis analysis. In Osaka-ryokuto six proteins were found in higher amounts compared to BC20 in the crude protein extract. Some of these proteins were homologous to legumin B and liguleless1. And in BC20 one unique protein, homologous to SalF1R, was identified. In the subcellular protein fractions, nine unique proteins were identified in BC20, seven in the cytosol and two in the membrane fractions. These proteins were homologous to chitinase, alanine aminotransferase in membrane, and SalF1R, β-1,3- glucanase, protein phosphatase 2A, peroxidase BP 2A, provicilin and canavalin in the cytosol fractions. Previous findings of many researchers reveal that these are mainly defence-related proteins. Thus, it is suggested that the above proteins may play a role in maintaining the resistance of line BC20.