Mungbean Improvement Research Articles

Genome-wide characterization of PEBP genes in Mung bean (Vigna radiata L.) with functional analysis of VrFT1 in relation to photoperiod

Mung bean (Vigna radiata L.), a widely cultivated legume, belongs to the Fabaceae family’s Papilionoideae subfamily. Although Phosphatidylethanolamine-binding protein (PEBP) genes have been identified in several plant species, their presence and function in mung bean remain largely unexplored. In this study, we identified seven VrPEBP genes from mung bean and classified them into four clades: FT, MFT, TFL and FT-like. Cis-regulatory element analysis revealed that VrPEBP genes may play a role in light, hormone, and stress responses. Quantitative real-time PCR (qRT-PCR) analysis indicated that VrPEBPs were constitutively expressed in various tissues. However, tissue-specific expression patterns were observed among VrPEBP genes. Under short-day (SD) conditions, VrFT1 and VrMFT1 exhibited significantly higher expression levels than under long-day (LD) conditions at 8 and 4 h, respectively. Conversely, VrTFL2 and VrTFL3 showed significantly higher expression levels under LD conditions compared to SD conditions at 8 and 12 h, respectively. The varied expression patterns of these genes under different photoperiod suggest their potential involvement in the photoperiodic regulation of flowering in mung bean. Additionally, phenotypic analysis of transgenic Arabidopsis plants overexpressing VrFT1 revealed higher expression levels under SD conditions and predicted its role in promoting flowering. These results provide valuable insights into the evolution and function of PEBP genes in mung bean and lay the foundation for further research on their regulatory mechanisms and potential applications in mung bean improvement.

Interrelationship Between Emergence and Yield Parameters in Mung Bean: Implication for Selection

Abstract Rapid and uniform seed germination and seedling emergence have been associated with grain yield under diverse environmental conditions. Twenty-one (21) mung bean accessions were evaluated at Ile-Ife and Kishi out-stations of the Institute of Agricultural Research and Training (IAR & T), Nigeria, to identify the emergence parameter(s) that could be selected for improvement of mung bean for yield. The experiment was laid out in a randomized complete block design (RCBD) in three replications. Data were collected on emergence and yield parameters and analysed using the Statistical Analysis Software (SAS). Mean, heritability, and correlation coefficient were estimated. Path coefficient analysis was used to partition correlations into direct and indirect effects using seed yield as the dependent variable. Heritability estimate was moderate to high for most of the traits. Accessions 3, 6, 14 and 15 with high pod and seed yield had also high values of coefficient of velocity of emergence (CVE) and emergence percentage (E%). All emergence parameters except emergence energy had significant correlation with yield traits. CVE and Emergence Index (EI) had strong positive correlation with number of seeds.pod-1 and pod yield. When only the emergence parameters were considered, CVE had highest direct effect (0.74) on seed yield followed by E% (-0.73) and EI (0.70). Total indirect effects of EI and CVE accounted for only 6.06% and 11.9% of the total correlation, respectively. It therefore suggests that EI and CVE are emergence parameters that could be selected for at early stage in improvement of mung bean for yield.

Estimation of genetic variability for seed yield and yield related traits in mungbean [Vigna radiata (L.) Wilczek

Genetic variability is the most important factor for the success of any crop improvement program. Hence, the evaluation of genotypes has to be conducted as a preliminary step to study the extent of variability available in the genotypes and to identify suitable high-yielding genotypes that can be utilized in the crop improvement program. The present investigation was carried out to estimate genetic variability, heritability, and genetic advance for yield and yield contributing characters among 38 genotypes of mungbean for eleven quantitative traits. Significant differences were observed among genotypes for all eleven characters studied. The high degree of genetic variability along with high heritability and high genetic advance as percent of mean were recorded for seed yield per plant, harvest index, number of pods per plant, plant height, and the number of branches per plant which indicates that these characteristics were under the control of additive gene action and therefore, form the basis of selection for the mungbean improvement program.

Studies on genetic variability parameters for seed yield and its component traits in mungbean [Vigna radiata (L.) Wilczek] germplasm under arid environment

Genetic variability is the most important factor for the success of any crop improvement program. Hence, the evaluation of germplasm has to be conducted as a preliminary step to study the extent of variability available in the germplasm and to identify suitable high-yielding genotypes that can be utilized in the crop improvement program. The present investigation was carried out to estimate genetic variability, heritability, and genetic advance for yield and yield contributing characters among seventy-nine diverse genotypes of mungbean for eleven quantitative traits. Significant differences were observed among genotypes for all eleven characters studied. The high degree of genetic variability along with high heritability and high genetic advance as percent of mean were recorded for seed yield per plant, number of pods per plant, harvest index, biological yield per plant, and plant height; which indicates that these characteristics were under the control of additive gene action and therefore, form the basis of selection for the mungbean improvement program.

Identification of heat-tolerant mungbean genotypes through morpho-physiological evaluation and key gene expression analysis.

Mungbean plays a significant role in global food and nutritional security. However, the recent drastic rise in atmospheric temperature has posed an imminent threat to mungbean cultivation. Therefore, this study investigates the growth and physiological changes of 87 mungbean germplasm lines under heat stress. Genotypes were examined using parameters including leaf area, chlorophyll content, membrane stability index (MSI), stomatal conductance, pollen viability, number of pods per cluster, number of pods per plant, number of seeds/pod, 100-seed weight and grain yield/plant under heat stress and control environments. A wide range of variation was observed for these traits among genotypes under heat stress and control environments. Genotypes were also identified with variable responses under both environments. The phenotypic expression of selected promising accessions was also validated in control environment conditions at the National Phytotron facility. The selected promising genotypes viz., IC76475, IC418452 and IC489062 validated their heat tolerance behavior for key candidate genes revealed by quantitative real-time PCR (qRT-PCR). These mungbean genotypes can act as potential resources in the mungbean improvement programs for heat stress tolerance. This study also provides a comprehensive understanding of the key mechanisms underlying heat tolerance in mungbean.

Leveraging genomics and phenomics to accelerate improvement in mungbean: A case study in how to go from GWAS to selection

AbstractGrown on 7 million ha, mungbean is a warm‐season grain legume with regional importance in parts of Asia and Africa. Under forecasted climate change, due to its tolerance to drought and heat, the short crop duration, and its nutritional properties, mungbean could serve to fill an important need for human diets. However, selection of accessions becomes difficult where plant and consumer market variation is large. We performed selection on genebank accessions, specifically the mini‐core collection at the World Vegetable Center, for yield and yield component traits. Our selection index uses refined accuracy by leveraging genomics, phenomics, and genotype‐by‐environment interactions. Best linear unbiased prediction (BLUP) is used to predict the genotypic effects of the 292 mini‐core accessions toward seed yield based on genomic relationships formed from ∼200,000 SNPs. We expanded BLUP analysis to predict phenotypic effects based on the phenomic relationships formed from ∼75,000 measurements from three‐dimensional multispectral data. While this method is restricted to a single environment, our multi‐environment trials across eight countries and 4 years serve to quantify the genotype‐by‐environment effect. K‐fold cross‐validation finds predictive ability to vary by methods but to be related to the narrow‐sense heritability of the yield component trait. Our weighted rank sum index (WRSI) linearly combines yield component traits to proxy yield within our single environment phenomics trial by first ranking genomic and/or phenomic BLUPs, then weighting by predictive accuracy from the cross‐validated model, and then summing the component weighted ranks for each accession. Selections were made from the predicted random effects in each location, identifying three accessions overlapping across both methodologies: PI 369787 (VI001339A‐G) and EG‐MD‐6D (VI000380A‐G) from the Philippines, and PI 363534 (VI003220A‐G) from India.

Genome-wise association study identified genomic regions associated with drought tolerance in mungbean (Vigna radiata (L.) R. Wilczek).

A total of 282 mungbean accessions were resequenced to identify genome-wide variants and construct a highly precise variant map, and drought tolerance-related loci and superior alleles were identified by GWAS. Mungbean (Vigna radiata (L.) R. Wilczek) is an important food legume crop that is highly adapted to drought environments, but severe drought significantly curtails mungbean production. Here, we resequenced 282 mungbean accessions to identify genome-wide variants and constructed a highly precise map of mungbean variants. A genome-wide association study was performed to identify genomic regions for 14 drought tolerance-related traits in plants grown under stress and well-watered conditions over three years. One hundred forty-six SNPs associated with drought tolerance were detected, and 26 candidate loci associated with more than two traits were subsequently selected. Two hundred fifteen candidate genes were identified at these loci, including eleven transcription factor genes, seven protein kinase genes and other protein coding genes that may respond to drought stress. Furthermore, we identified superior alleles that were associated with drought tolerance and positively selected during the breeding process. These results provide valuable genomic resources for molecular breeding and will accelerate future efforts aimed at mungbean improvement.

Genome wide association analysis for grain micronutrients and anti-nutritional traits in mungbean [Vigna radiata (L.) R. Wilczek] using SNP markers.

Mungbean is an important food grain legume for human nutrition and nutritional food due to its nutrient-dense seed, liked palatability, and high digestibility. However, anti-nutritional factors pose a significant risk to improving nutritional quality for bio-fortification. In the present study, genetic architecture of grain micronutrients (grain iron and zinc concentration) and anti-nutritional factors (grain phytic acid and tannin content) in association mapping panel of 145 diverse mungbean were evaluated. Based on all four parameters genotypes PUSA 1333 and IPM 02-19 were observed as desired genotypes as they had high grain iron and zinc concentration but low grain phytic acid and tannin content. The next generation sequencing (NGS)-based genotyping by sequencing (GBS) identified 14,447 genome-wide SNPs in a diverse selected panel of 127 mungbean genotypes. Population admixture analysis revealed the presence of four different ancestries among the genotypes and LD decay of ∼57.6 kb kb physical distance was noted in mungbean chromosomes. Association mapping analysis revealed that a total of 20 significant SNPs were shared by both GLM and Blink models associated with grain micronutrient and anti-nutritional factor traits, with Blink model identifying 35 putative SNPs. Further, this study identified the 185 putative candidate genes. Including potential candidate genes Vradi07g30190, Vradi01g09630, and Vradi09g05450 were found to be associated with grain iron concentration, Vradi10g04830 with grain zinc concentration, Vradi08g09870 and Vradi01g11110 with grain phytic acid content and Vradi04g11580 and Vradi06g15090 with grain tannin content. Moreover, two genes Vradi07g15310 and Vradi09g05480 showed significant variation in protein structure between native and mutated versions. The identified SNPs and candidate genes are potential powerful tools to provide the essential information for genetic studies and marker-assisted breeding program for nutritional improvement in mungbean.

Genetic and Genomics Resources of Cross-Species Vigna Gene Pools for Improving Biotic Stress Resistance in Mungbean (Vigna radiata L. Wilczek)

Mungbean (Vigna radiata L. Wilczek) is an important short-duration grain legume of the genus Vigna that has wider adaptability across agro-climatic regions and soil types. Significant strides have been made towards the development of superior, high-yielding, and climate resilient cultivars in mungbean. A number of donors for various traits to have been deployed in introgression breeding. However, the use of common sources of resistance to different biotic stresses may lead to boom and bust cycles due to the appearance of new races or biotypes. Therefore, broadening the genetic base using wild and exotic plant genetic resources may offer a better quality of durable resistance. Many crop wild relatives (CWRs) confer a high degree of resistance against multiple diseases. Recently, several agronomically important genes have been mapped using inter-specific populations, which are being deployed for the improvement of mungbean. In such a situation, tagging, mapping, and exploiting genes of interest from cross-species donors for stress tolerance will offer novel genetic variations. This will also provide increased opportunities for the selection of desirable types. Advances in genomics and transcriptomics have further made it easy to tag the cross-compatible resistance loci and study their expression for delineating the mechanism of resistance. The comparative analysis of omics technology also helps in understanding the evolution and offers a scope for using cross-specific target genes for mungbean improvement. This review focuses on the effective utilization of cross-species cultivated and wild relatives as well as their omics resources for breeding multiple disease-resistant mungbean cultivars.

Correlation and Path Analysis Studies of Pod Yield and its Component Traits in Mungbean [Vigna radiata (L.) Wilczek] Genotypes

Background: Mungbean is an important pulse crop grown in India. The mungbean is an excellent source of protein (27%) and its essential amino acid comparable with that of soybean and kidney bean. Estimates of correlation coefficient are useful in identifying the component traits which can be used for yield improvement of mungbean. Path coefficient analysis provides a thorough understanding of contribution of various characters by partitioning the correlation coefficient into components of direct and indirect effects. This study aimed to quantify the relationship and contributions of various traits to seed yield. Methods: The present investigation was undertaken to assess the correlation and path analysis on yield and its components in 38 genotypes of mungbean. The genotypes were raised in randomized block design with three replications during Kharif 2019 at Agricultural Research Station Farm, Agriculture University, Jodhpur, Rajasthan. Result: The experimental results showed that positive correlation and positive direct effect on seed yield were observed for plant height, number of pods per plant, number of seeds per pod and 100 seed weight. Therefore these traits can be used for mungbean improvement program as well as developing high yielding varieties of mungbean.

Association mapping for important agronomic traits in wild and cultivated Vigna species using cross-species and cross-genera simple sequence repeat markers.

The genus Vigna is an agronomically important taxon, with many of its species inhabiting a wide range of environments and offering numerous useful genes for the improvement of the cultivated types. The present study aimed to detect the genomic regions associated with yield-attributing traits by genome-wide association mapping. A diverse panel of 98 wild and cultivated Vigna accessions (acc.) belonging to 13 different species was evaluated for yield and related traits during the kharif season of 2017 and 2018. The panel was also genotyped using 92 cross-genera and cross-species simple sequence repeat markers to study the population genetic structure and useful market-trait associations. The PCA and trait correlation established relationships amongst the traits during both seasons while 100-seed weight (HSW) had a positive correlation with pod length (PL), and days to first flowering (DFF) with days to maturity (DM). The population genetic structure analysis grouped different acc. into three genetically distinct sub-populations with SP-1 comprising 34 acc., SP-2 (24 acc.), and SP-3 (33 acc.) and one admixture group (7 acc.). Mixed linear model analysis revealed an association of 13 markers, namely, VR018, VR039, VR022, CEDG033, GMES0337, MBSSR008, CEDG220, VM27, CP1225, CP08695, CEDG100, CEDG008, and CEDG096A with nine traits. Seven of the aforementioned markers, namely, VR018 for plant height (PH) and terminal leaflet length (TLL), VR022 for HSW and pod length (PL), CEDG033 for DFF and DM, MBSSR008 for DFF and DM, CP1225 for CC at 30 days (CC30), DFF and DM, CEDG100 for PH and terminal leaflet length (TLL), and CEDG096A for CC30 and chlorophyll content at 45 days were associated with multiple traits. The marker CEDG100, associated with HSW, PH, and TLL, is co-localized in gene-encoding histone-lysine N-methyltransferase ATX5. Similarly, VR22, associated with PL and HSW, is co-located in gene-encoding SHOOT GRAVITROPISM 5 in mungbean. These associations may be highly useful for marker-assisted genetic improvement of mungbean and other related Vigna species.

Correlation and Path Coefficient Analysis in Rainfed Mung Bean Genotypes [Vigna radiata (L.) Wilczek)

Correlation and path analysis was carried out using sixteen genotypes of mung bean for eight component characters including seed yield. Field experimental was laid out under a randomized block design with three replications; observation was recorded on ten plants were selected at random from each plot for plant height, pod length, number of seeds per pod, test weight, seed yield per plot and seed yield per hectors whereas for days to 50% flowering and days to maturity data were recorded on whole plot basis among the genotypes of mung bean. The plant height, pod length and test weight had positive correlation with seed yield both at genotypic and phenotypic levels. Days to flowering, days to maturity and no. of seeds per pod had negative correlation with seed yield both at genotypic and phenotypic levels. Path analysis showed positive and high direct effect of days to maturity, pod length, seed yield per hectors and negative & high direct effect of days to flowering, plant height, test weight, whereas indirect effects of other component characters through these characters towards seed yield per plot. Hence, these traits should be given more emphasis while selecting genotypes for yield improvement in mung bean.

Consensus genetic map and QTLs for morphological and agronomical traits in mungbean using DArT markers.

Mungbean is an important but understudied food legume compared with other major grain crops. Genetic studies through development of high-through put markers, linkage map construction and QTL analysis can accelerate and improve the efficiency of mining for genes for breeding in this crop. This study used four mungbean F5 recombinant inbred lines (RILs) from crosses of two wild types (ACC 1, ACC 87) and two cultivars (Berken, Kiloga) and DArT markers to construct individual and consensus linkage maps and to identify QTLs associated with 54 traits in mungbean. The number of polymorphic DArT markers identified among the four RIL populations varied from 1062 to 2013. The individual maps covered the lengths of 629.7-883.5cM, comprising 672-981 DArT markers and 15-19 linkage groups (LG) with average distance between markers of 0.9-1.2cM. The consensus map had the total length of 795.3cM, comprising 1539 DArT markers and resolved 11 LGs with an average inter-marker distance of 0.65cM. Sixty-two QTLs were identified for 39 traits across 10 LGs of the consensus map. Major QTLs were identified for two special traits, late flowering inherited from ACC 1 (6 QTLs, PVE of 11.2-29.9%) and perenniality inherited from ACC 87 (3 QTLs, PVE of 17.4-22.6%) in separate population analysis. Number of congruent QTLs across four mungbean populations and the consensus map was 18 for 13 traits. These results illustrated the high efficiency of DArT marker application in mungbean genetic dissection and suggested the future potential employment of identified QTLs for mungbean improvement.

Phosphorus Deficiency Induced Physiological and Antioxidant Response in Mungbean

Background: Phosphorus (P) is the essential nutrient required for the growth and development of plants. P deficiency mainly leads to dark green foliage, alteration of root architectural traits and higher root to shoot ratio in plants. Further P deficiency results in enhancement of reactive oxygen species (ROS), thereby it leads to oxidative damage to plant cells. Plants have developed the mechanisms like production of antioxidants to overcome this effect. Methods: In the present study, 18 genotypes were evaluated under a hydroponic system with normal and low P levels. After 21 days, the seedlings were used for investigating the physiological and antioxidant activity response of genotypes under normal and low P condition. Result: The mean values of traits chlorophyll concentration, root dry weight, root to shoot ratio, H2O2, FRAP and DPPH were significantly higher under low P condition compared to normal P condition. The correlation and principal component analysis revealed that the traits RDW and TDW are major contributors to variation and could be used for P deficiency screening in mungbean. Based on major contributing traits of variation, the genotypes PUSA 1333 was identified as an efficient genotype and could be used in P use efficiency improvement in mungbean.

Genome-Wide Analysis of Late Embryogenesis Abundant Protein Gene Family in Vigna Species and Expression of VrLEA Encoding Genes in Vigna glabrescens Reveal Its Role in Heat Tolerance.

Late embryogenesis abundant (LEA) proteins are identified in many crops for their response and role in adaptation to various abiotic stresses, such as drought, salinity, and temperature. The LEA genes have been studied systematically in several crops but not in Vigna crops. In this study, we reported the first comprehensive analysis of the LEA gene family in three legume species, namely, mung bean (Vigna radiata), adzuki bean (Vigna angularis), and cowpea (Vigna unguiculata), and the cross-species expression of VrLEA genes in a wild tetraploid species, Vigna glabrescens. A total of 201 LEA genes from three Vigna crops were identified harboring the LEA conserved motif. Among these 55, 64, and 82 LEA genes were identified in mung bean, adzuki bean, and cowpea genomes, respectively. These LEA genes were grouped into eight different classes. Our analysis revealed that the cowpea genome comprised all eight classes of LEA genes, whereas the LEA-6 class was absent in the mung bean genome. Similarly, LEA-5 and LEA-6 were absent in the adzuki bean genome. The analysis of LEA genes provides an insight into their structural and functional diversity in the Vigna genome. The genes, such as VrLEA-2, VrLEA-40, VrLEA-47, and VrLEA-55, were significantly upregulated in the heat-tolerant genotype under stress conditions indicating the basis of heat tolerance. The successful amplification and expression of VrLEA genes in V. glabrescens indicated the utility of the developed markers in mung bean improvement. The results of this study increase our understanding of LEA genes and provide robust candidate genes for future functional investigations and a basis for improving heat stress tolerance in Vigna crops.

Combining Ability Studies for Seed Yield and its Quantitative Traits in F2 Crosses of Mungbean [Vigna radiata (Wilczek)

Background: Combining ability is a measure that enables breeders to select better parents and outstanding hybrids. General combining ability and specific combining ability is used to determine best performing parents and vigorous hybrids respectively and provides an opportunity to understand the nature of gene action involved in inheritance of each character. Methods: A combining ability analysis was carried out with six mungbean varieties and their 15 F2 crosses derived from half diallel fashion. Data was recorded for 10 characters and were subjected to statistical analysis using method-II and model-1 of Griffing’s approach. Result: There was importance of both additive and non-additive gene action in inheritance of all the characters as apprehended from significant values in mean sum of square due to GCA and SCA. Studies on components of variance due to GCA and SCA indicated there was preponderance of additive gene action for days to 50% flowering, days to maturity and pod length whereas non-additive gene action was expressed for other characters. Four parents viz., Kamdev, Pant Mung-8, MGG-385 and OBGG-52 were considered as best general combiners on the basis of significant GCA effects for a number of yield and its related traits. Based on SCA effects and per se performance, the crosses IPM-02-14/OBGG-58, OBGG-52/OBGG-58 and MGG-385/OBGG-52 displayed significant SCA in desirable direction along with high mean for many of the yield attributing characters. Highest significant SCA for seed yield was observed by the cross Kamdev/IPM-02-14. These selected parents and crosses can be used for further breeding programmes for crop improvement in mungbean.

Mungbean (Vigna radiata (L.) R. Wilczek): Progress in Breeding and Future Challenges

Mungbean (Vigna radiata (L.) R. Wilczek) is a short duration farmer preferred warm-season pulse crop. The crop has shown a balanced growth worldwide, especially in developing countries. Mungbean being a great source of protein with higher folate and iron levels attracts high demand and price on the market making the farmers happy and satisfied. Moreover, it can fix atmospheric nitrogen through symbiosis with nitrogen-fixing bacteria, making it perfect for rice based cropping systems and intercropping with other crops. Despite having so many benefits, mungbean has been a neglected crop compared to other pulses with limited efforts aiming at its breeding and development. Higher productivity, breeding for biotic and abiotic stresses resistance and nutritional quality improvement are future challenges for mungbean breeders. Several researchers are working in the direction of collecting and maintaining mungbean genetic resources. Mutation breeding and genetic engineering has also been enhanced in mungbean varietal improvement. Genomic information is limited compared to other legume species. However, the recent successful sequencing of mungbean genome has opened new vistas into the crop’s R&D. It is a self-pollinated pulse with small genome size, which could be used as a model for studying other legumes. Mungbean breeders at present times aim to identify useful alleles from diverse germplasm and markers closely associated with desirable traits. The high-throughput marker genotyping system has now made it feasible to pinpoint the exact gene locations and mutations contributing target phenotypes. In this review we present the current status of conventional and molecular breeding of the crop and summary of efforts in the utilization of genetic information and genomic resources for further mungbean improvement.

Dissecting the Root Phenotypic and Genotypic Variability of the Iowa Mung Bean Diversity Panel.

Mung bean [Vigna radiata (L.) Wilczek] is a drought-tolerant, short-duration crop, and a rich source of protein and other valuable minerals, vitamins, and antioxidants. The main objectives of this research were (1) to study the root traits related with the phenotypic and genetic diversity of 375 mung bean genotypes of the Iowa (IA) diversity panel and (2) to conduct genome-wide association studies of root-related traits using the Automated Root Image Analysis (ARIA) software. We collected over 9,000 digital images at three-time points (days 12, 15, and 18 after germination). A broad sense heritability for days 15 (0.22–0.73) and 18 (0.23–0.87) was higher than that for day 12 (0.24–0.51). We also reported root ideotype classification, i.e., PI425425 (India), PI425045 (Philippines), PI425551 (Korea), PI264686 (Philippines), and PI425085 (Sri Lanka) that emerged as the top five in the topsoil foraging category, while PI425594 (unknown origin), PI425599 (Thailand), PI425610 (Afghanistan), PI425485 (India), and AVMU0201 (Taiwan) were top five in the drought-tolerant and nutrient uptake “steep, cheap, and deep” ideotype. We identified promising genotypes that can help diversify the gene pool of mung bean breeding stocks and will be useful for further field testing. Using association studies, we identified markers showing significant associations with the lateral root angle (LRA) on chromosomes 2, 6, 7, and 11, length distribution (LED) on chromosome 8, and total root length-growth rate (TRL_GR), volume (VOL), and total dry weight (TDW) on chromosomes 3 and 5. We discussed genes that are potential candidates from these regions. We reported beta-galactosidase 3 associated with the LRA, which has previously been implicated in the adventitious root development via transcriptomic studies in mung bean. Results from this work on the phenotypic characterization, root-based ideotype categories, and significant molecular markers associated with important traits will be useful for the marker-assisted selection and mung bean improvement through breeding.

MOLECULAR CHARACTERIZATION OF RHIZOBIA STRAINS ASSOCIATED WITH MUNGBEAN (VIGNA RADIATA), IN SOILS OF SUDANO-GUINEAN AND SAHELIAN AGROECOLOGICAL ZONES OF MALI

In the Sudano-Guinean and Sahelian zones of Mali, the decline in soil fertility is a key challenge for a sustainable enhancement of agricultural productivity. In addition, studies on the diversity of bacteria associated with Mungbeans are rare, with very few studies conducted on their identification and molecular characterization in the soils of the major agricultural production basins in the Sudano-Guinean and Sahelian Guinean zones of Mali. This study was therefore motivated not only by these different challenges of productivity and soil fertility, but also by the numerous nutritional and agronomic interests of mung beans and the possibility of using its associated bacteria as bio-fertilizers. It aims at contributing to the improvement of mung bean (Vigna radiata L) productivity and the promotion of its cultivation using inocula based on indigenous and efficient bacteria. To achieve this objective, soil samples were taken from various farmers' fields in the two studied areas. The Physico-chemical characteristics of the soils were determined, and trapping trials were conducted in the greenhouse on these soils with Mung bean as the trap plant. The nodules formed on the plants were harvested, the rhizobia contained in these nodules were isolated, the IGS of the 16S-23S rDNA of the isolates was analyzed using PCR-RFLP, and an inoculation test was carried out in a growth chamber to verify the infectivity of the isolates. Eighty-three (83) isolates divided into two groups according to their color (whitish, yellowish) and three (03) IGS types (I, II, III) were encountered with a large dominance of IGS type I in the Guinean zone and that of IGS types I and II in the Sahel zone. Two (02) isolates of type IGS I showed a higher infectivity. These results show a low diversity of rhizobium strains associated with Mung bean in the studied soils. It would be interesting to extend this study to other areas of Mali for strains that associate with Mung bean.

Mutation Breeding: A Way Forward for Genetic Improvement in Mungbean

Mungbean is a major food leguminous crop mainly cultivated in Asia. It is famous for its high protein, carbohydrate, and nutritional content. With the help of microorganisms located in their root nodules, the crop also maintain soil fertility through biological nitrogen fixation. This not only allows them to meet their own nitrogen needs, but it also improves the production of succeeding crops. One of the prerequisites for crop improvement is the availability of genetic variability. The capability to select improved genotypes in mungbean is limited by a lack of necessary diversity. Chemical and physical mutagens are frequently employed in Plant Mutation Breeding to boost crop productivity and resistance to diseases, insects, drought, and salt by creating genetic variability in crop plants. Mungbean is an early maturing crop often cultivated on low-fertility land with minimal inputs. In the case of these crops, the selection pressure has been focused on stress adaptation rather than yield. As a result, improving the genetics of such crops to increase yield necessitates genetic reconstitution to generate diverse plant types. Induced mutations can contribute to the regeneration and restoration of diversity that has been lost during the evolutionary process because of various pressures or adaptations. Thus, induced mutation or mutation breeding has a lot of potential for improving traditional agricultural crops like mungbean. In this paper, we look at many forms of mutations identified in mungbean crops by various scientists.