Introduction (Scientific name, family and chromosome number)
Mungbean — Vigna radiata (L.) R. Wilczek — is a short-duration, warm-season annual pulse crop belonging to the family Fabaceae (Leguminosae). It is diploid with a chromosome number of 2n = 22. Mungbean is grown for its dry seeds, green pods and tender seeds, and also as a forage/cover crop. It is valued for high protein, rapid growth and nitrogen-fixation ability.
Centre of Origin
Mungbean originated in South and Southeast Asia, with the Indian subcontinent and Indo–Burma region considered the primary centres of domestication. Archaeobotanical and genetic studies confirm early cultivation in these regions.
Distribution of Species
Mungbean is widely grown across tropical and subtropical Asia — India, Pakistan, Bangladesh, Myanmar, Thailand, Vietnam, China, Indonesia and the Philippines. It is also cultivated in parts of Africa, northern Australia and the Americas under suitable conditions.
Cultivated Species
The main cultivated form is Vigna radiata var. radiata. This domesticated type has larger seeds, non-shattering pods, and erect or semi-erect habits. Varieties differ in maturity (45–120 days), plant habit (prostrate to erect), seed size, seed coat colour (green, yellow, brown, black) and uses (grain, vegetable, fodder). Short-duration types (45–60 days) are widely used in multiple cropping systems, while medium- and long-duration types are preferred for higher biomass and grain.
Wild Species
The immediate wild progenitor is Vigna radiata var. sublobata, which has small seeds, twining habit and shattering pods. Related species like V. umbellata (ricebean), V. aconitifolia (moth bean), and V. mungo (black gram) provide resistance and stress-tolerance genes useful in breeding.
Botanical Description
Mungbean is an annual, mostly self-pollinated herb. Root and stem: Deep taproot with nodules; erect to semi-erect stems. Leaves: Alternate, trifoliate. Flowers: Small yellow papilionaceous flowers borne in axillary racemes. Pods: Slender, 2–5 cm, 4–8 seeds. Seeds: Oval to oblong, coat colour variable. Reproduction is mainly by selfing, though insect-mediated outcrossing occurs at low levels.
Economical Importance
- Protein-rich pulse: Seeds contain 23–28% protein, highly digestible.
- Vegetable and sprouts: Consumed as green pods and sprouts, important in urban diets.
- Soil fertility: Nitrogen-fixation enhances soil health for following crops.
- Fodder and green manure: Useful in livestock feeding and soil improvement.
- Processing and trade: Consumed as dal, flour, starch and sprouts; export commodity.
Breeding Objectives
- High and stable yield.
- Short duration and synchronous maturity.
- Tolerance to drought, heat, salinity and waterlogging.
- Resistance to MYMV, powdery mildew, Cercospora leaf spot, anthracnose, bruchids.
- Seed quality: larger size, better protein, micronutrients (Fe, Zn), cooking quality.
- Improved plant type: determinate, erect, non-shattering, lodging-resistant.
- Hybrid development to exploit heterosis where feasible.
Important Breeding Methods
Conventional Approaches
- Germplasm collection and evaluation: For trait-specific donors.
- Pure-line selection: Effective due to self-pollination.
- Hybridization and pedigree selection: Combining yield, resistance, and quality.
- Backcross breeding: For introgressing major genes like MYMV resistance.
- Mutation breeding: To induce variability in seed size, maturity, habit.
- Recurrent selection: Accumulating favourable alleles for yield and stress tolerance.
- Hybrid breeding: Using male-sterility systems with insect pollinators for heterosis.
Innovative Approaches
- Molecular markers & MAS: Accelerates resistance introgression (MYMV, QTLs).
- Genomics: Genome sequencing, QTL mapping, genomic selection for complex traits.
- Gene editing (CRISPR/Cas): Precise modification of flowering, resistance and quality genes.
- Speed breeding: Rapid generation advancement under controlled conditions.
- Precision phenotyping: Imaging, sensors for canopy temperature and NDVI.
- Interspecific hybridization: Using wild relatives for resistance and tolerance.
- Biofortification: Iron, zinc and protein-rich cultivars with low anti-nutritional factors.
- Participatory breeding: Farmer-preferred seed traits, cooking quality, market value.
Breeding for Specific Stresses
Biotic: MYMV resistance through MAS and donor introgression; bruchid resistance for storage; resistance to powdery mildew, Cercospora and anthracnose. Abiotic: Drought (deep rooting, early maturity), heat (pollen fertility), salinity and waterlogging tolerance. Quality: Large seed size, preferred colour, high protein, improved cooking time, micronutrient enrichment.
Challenges and Prospects
Challenges include limited natural outcrossing, small flowers, complex G×E for yield, and weak seed systems. Prospects lie in integrating genomics, gene editing, pre-breeding, and hybrid technology with strong participatory approaches and improved seed dissemination.
Conclusion
Mungbean is a highly important pulse for food, nutrition and soil health. Combining conventional breeding with modern genomics and biotechnology can deliver cultivars with higher yield, stress resilience and nutritional quality. Future breeding must integrate diverse germplasm, farmer participation and efficient seed systems to enhance adoption and impact.
