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Vigna mungo

Vigna mungo (L.) Hepper, commonly known as black gram, urd bean, urad dal, or black matpe bean, is an annual herbaceous in the family , native to the and widely cultivated in South and Southeast Asia. It grows as an erect to twining, hairy, bushy plant reaching 30–100 cm in height, with a well-developed , diffusely branched stems, and trifoliate leaves composed of three oval to ovate leaflets. The plant produces small flowers, 12 mm long, in dense axillary clusters or head-like racemes on long peduncles, followed by cylindrical, hairy pods 4–7 cm long with a short hooked , each containing 4–10 black or dark brown seeds. The seeds of V. mungo are highly nutritious, providing a rich source of protein (approximately 24–25 g per 100 g), , minerals such as calcium, iron, and , and bioactive compounds, making it a vital in South Asian diets. They are consumed whole, split and dehusked as , or ground into flour for traditional dishes like , dosa, vada, and soups, often boiled or sprouted to enhance digestibility despite natural anti-nutritional factors like and inhibitors. Beyond human consumption, the plant serves as for , a to improve through , and occasionally as a substitute from its seed flour. In traditional medicine, various parts are used to treat ailments including dyspepsia, , , and hepatopathy. India dominates global production of black gram, accounting for over 70% of the world's output, primarily during the kharif (rainy) season, with total production of approximately 2.8 million tonnes annually from about 4.6 million hectares as of 2023–24. The crop thrives in warm climates with temperatures of 25–35°C, tolerating a wide range from 8–40°C, and is often intercropped with cereals like or on well-drained loamy soils with pH 6–7.5, contributing to by enhancing soil structure and nutrient availability.

Taxonomy and Description

Taxonomy

_Vigna mungo is classified within the kingdom Plantae, Tracheophyta, Magnoliopsida, Fabales, family , subfamily , Vigna, and V. mungo (L.) Hepper. The is a native to the , belonging to the subgenus Ceratotropis of the Vigna. Historically, V. mungo was known as , a name under which it was first described by in 1753, before its reclassification to the genus in the mid-20th century by Frank Nigel Hepper, reflecting phylogenetic distinctions within the . Other synonyms include Azukia mungo (L.) Masam. and Rudua mungo (L.) Maekawa, all homotypic to the accepted name. Close relatives include Vigna radiata () and Vigna unguiculata (), both in the same genus and sharing the diploid chromosome number 2n=22, though V. mungo is distinguished from V. radiata by its black seed coat and other morphological traits such as pod hair length and seed hilum structure. The wild progenitor of cultivated V. mungo is V. mungo var. silvestris, from which occurred in the . Phylogenetically, V. mungo forms part of the Asian clade within subgenus Ceratotropis, showing monophyletic relationships with other cultivated Asian Vignas like V. radiata, supported by analyses that highlight independent lineages from distinct wild ancestors. This positioning underscores its evolutionary divergence within the , with genetic studies confirming its basal role in the subgenus's radiation approximately 2.9–3.6 million years ago.

Physical Description

Vigna mungo is an erect, hairy, bushy annual herb that typically grows to a height of 30-100 , occasionally twining at the tips. It possesses a well-developed with an extensive branched , including smooth, rounded nodules that facilitate symbiotic with bacteria, enhancing . The stem is diffusely branched from the base, lightly ridged, and covered in fine hairs. Leaves are arranged alternately and are trifoliate, with ovate-lanceolate leaflets measuring 5-10 in length that are densely pubescent, providing a protective layer against environmental stresses. Flowers are bright yellow and papilionaceous, borne in axillary racemes containing 4-10 blooms per cluster; the plant is primarily self-pollinating, though insect pollination can occur. Fruits consist of narrow, cylindrical pods, 4-6 long and about 5 mm wide, which are slightly hairy and held erect on short peduncles; each pod contains 5-10 small, ellipsoid seeds, 3-4 mm in length, typically black with a prominent white hilum. As an annual species, V. mungo exhibits , with cotyledons and the stem emerging above ground within 4-7 days under optimal conditions. Flowering commences 40-50 days after , leading to pod development, with full maturity reached in 90-120 days depending on variety and environment. The plant is drought-tolerant, owing to its deep system that accesses subsoil moisture and pubescent stems and leaves that minimize and water loss.

History and Domestication

Origins

Vigna mungo, commonly known as black gram or urd bean, originated in the , with its wild progenitor, V. mungo var. silvestris, distributed across regions including the Indo-Gangetic plains and parts of . The wild form exhibits traits typical of undomesticated , such as shattering pods and smaller seeds, and is found in similar ecological niches to early cultivation sites. Domestication of V. mungo occurred approximately 3,500 to 4,500 years ago, around 1500–2500 BCE, during the late Harappan and early periods in . Archaeological evidence includes charred seeds recovered from ancient settlements in , such as Navdatoli and Bagasra, indicating early cultivation alongside other pulses like (V. radiata). These findings suggest integration into mixed cropping systems in the semi-arid and alluvial plains, marking a key phase in South Asian agricultural development. The process involved human selection for advantageous traits from the wild progenitor, including non-shattering pods to facilitate seed harvest, larger seed size for improved yield, and reduced for synchronized . Following domestication, V. mungo spread from the to and later to parts of , likely through routes and , adapting to diverse tropical agroecosystems. Genetic studies support this history, confirming divergence of V. mungo from its close relative V. radiata around 2.7 million years ago, with molecular markers revealing reduced diversity in cultivated forms indicative of a during South Asian . Genome-wide analyses link these changes to early agricultural revolutions in the region, where selective pressures shaped traits essential for farming.

Historical Significance

Vigna mungo, commonly known as black gram or urad, holds a prominent place in ancient history, referenced in Vedic texts around 1500 BCE as "masha," underscoring its longstanding role as a valued in early agrarian societies. These texts highlight its integration into daily sustenance and ritual practices, reflecting its nutritional and symbolic value from the outset of recorded . In the Indus Valley Civilization, black gram formed a key component of the diet, cultivated alongside staples like () and (), as evidenced by archaeobotanical remains from Late Harappan sites dating to approximately 2000–1200 BCE. Archaeological insights from these early urban centers, including evidence of pulse processing, illustrate the transition from wild foraging of its progenitor, Vigna mungo var. silvestris, to systematic cultivation, marking black gram's evolution into a foundational in South Asian farming systems. Black gram's significance expanded through trade networks, with exports to occurring via early maritime routes as part of the broader dissemination of agricultural goods around 200 BCE–AD 20. In the , it featured prominently in cuisine (16th–19th centuries CE), where split urad dal served as a base for rich preparations like , a fried sweet symbolizing the era's culinary sophistication and fusion of local ingredients with influences. Under British colonial rule in (18th–20th centuries CE), black gram was recognized as a vital pulse crop in agricultural policies, supporting mixed cropping systems and contributing to in rural regions amid expanding commercial farming. Culturally, black gram embodies prosperity in folklore, often depicted as a symbol of abundance and fertility due to its hardy growth and yield potential in diverse s. It plays a central role in Hindu rituals and festivals, such as offerings during Navratri or incorporation into sattvic dishes for religious observances, reinforcing community bonds and spiritual practices across generations. Economically, as a staple , it has sustained rural livelihoods in by providing affordable protein and nitrogen-fixing benefits to , underpinning smallholder farming economies historically and into the present.

Cultivation Practices

Growing Conditions

Vigna mungo, commonly known as black gram, thrives in warm tropical and subtropical climates, with optimal daytime temperatures ranging from 25°C to 35°C for growth and development. The crop exhibits tolerance to conditions and can withstand temperatures up to 40°C, though it is highly sensitive to and performs poorly below 8°C. It requires annual rainfall of 600-1000 mm, well-distributed during the growing period, or supplemental irrigation in drier areas to support pod formation. The plant prefers well-drained sandy or loamy soils with a range of 6.0 to 7.5, which facilitates development and uptake. While it shows moderate to , black gram is highly susceptible to waterlogging, which can lead to and reduced yields, necessitating soils with good drainage. As a , it benefits from symbiotic with , enhancing without heavy reliance on external inputs. Sowing typically occurs during the kharif season from June to July or the rabi season from October to November, depending on regional monsoon patterns and residual soil moisture. A seed rate of 20-25 kg per hectare is recommended, with seeds treated using Rhizobium inoculant prior to planting to promote nodulation. Spacing is generally 30 cm between rows and 10 cm between plants for irrigated conditions, or slightly closer at 25 cm x 10 cm for rainfed systems to optimize light interception and reduce weed competition. Effective management includes timely weeding, such as manual removal or post-emergence herbicides like imazethapyr at 20-25 days after sowing, to control broadleaf and grassy weeds. Pest management focuses on integrated approaches against common threats like pod borers (Helicoverpa armigera), using pheromone traps, neem-based biopesticides, or insecticides applied at flowering and podding stages. Black gram reaches maturity in 90-120 days, depending on variety and season, with initial pod set occurring around 60-65 days after sowing. Harvesting is done when 70-80% of the pods have turned black and dried, to minimize seed shattering from over-maturity; plants are uprooted by hand or mechanically cut close to the ground, followed by drying in the field or under cover before threshing.

Production and Distribution

India is the world's largest producer of Vigna mungo, commonly known as black gram or urad bean, accounting for approximately 69% of global output and producing around 2.6 million metric tons in 2024 from about 4.0–4.5 million hectares. Other major producers include , with an estimated annual output of approximately 1.0–1.1 million metric tons in 2024–25, followed by and at smaller scales of under 0.1 million metric tons each; production remains minor in and the , contributing less than 5% to the global total. The global production of black gram reached 3.8 million metric tons in 2024, predominantly concentrated in , where over 90% of cultivation occurs due to favorable climatic conditions and established farming systems. Distribution patterns emphasize South Asia's dominance, with black gram often intercropped with cereals like or to enhance and promote in resource-limited regions. Significant exports occur primarily from and , where the crop is processed into (split and dehusked form) and shipped to the Middle East, , and to meet demand for protein-rich staples in diets. Trade volumes have grown steadily, with exporting over 400,000 tons in the first half of 2023–2024 alone, supporting regional and import needs in deficit countries. Average yields for black gram range from 700 to 1,000 kg per , though these vary by region and management practices, with India's national average at about 657 kg/ in 2022–2023. Challenges such as climate-induced droughts and infestations, including bruchids and pod borers, have reduced outputs by 20–30% in recent years, particularly during vulnerable flowering stages in rainfed areas. Recent trends indicate variability, with India's production estimated at 2.32 million tonnes in 2023–24 and 2.11 million tonnes in 2024–25 (first advance estimates as of November 2025), reflecting impacts from weather and acreage changes despite adoption of improved varieties. This aligns with broader FAO data on pulses, showing global production increasing to support nutritional goals, though black gram's share remains stable amid efforts to mitigate environmental pressures.

Culinary Applications

Processing and Preparation

After harvesting, the pods of Vigna mungo are dried to a moisture content of 12-14% to prevent and ease separation of . This drying is typically achieved by spreading the harvested on floors under the sun for several days. Threshing follows, using manual beating with sticks or threshers to separate the black seeds from the pods, yielding whole urad dal. For split urad dal, the seeds undergo dehulling to remove the seed and subsequent splitting into halves, either retaining the skin or producing skinless varieties through abrasive milling processes. Cleaned seeds are stored in cool, dry environments (ideally below 25°C and 12% relative humidity) in airtight containers to minimize insect infestation and moisture absorption, maintaining viability for up to 12 months. Milling of whole or split urad dal produces urad atta, a fine flour used in batter preparations; this process involves grinding dried seeds after conditioning to optimal moisture. Soaking the dal in water for 4-8 hours prior to cooking significantly reduces required cooking time by approximately 50%, enhancing digestibility by softening the cotyledons. For fermented products, urad dal is soaked (typically 4 hours at 30°C), ground into a smooth batter often mixed with , and subjected to natural by indigenous microorganisms over 8-12 hours at around 30°C, resulting in a slightly acidic, aerated mixture suitable for steamed or griddled foods. Preservation methods include of urad into thin sheets for papads, which are sun-dried to below 10% moisture for extended . Processed forms such as canned or urad are also utilized for , ensuring stability during .

Regional Dishes

In , Vigna mungo, commonly known as urad or black gram, serves as a core ingredient in various traditional dishes, particularly in the south where split and dehusked seeds are fermented with to create batters for steamed idlis, crispy dosas, and fried medu vadas. These fermented preparations are staples of daily meals and breakfasts, valued for their light texture and qualities derived from natural lactic . In northern regions, whole urad is central to , a creamy, slow-cooked enriched with butter, cream, tomatoes, and spices like and , often served with or as a comforting . Urad flour is also dried and seasoned to produce papads, thin crisps that are roasted or fried as accompaniments to curries and meals across the country. Beyond India, urad dal features in select Asian culinary traditions, such as Burmese street foods where it is formed into fritters alongside and for snacks. In , it forms the base of mash ki daal, a spiced, tempered preparation similar to northern styles but often drier and paired with or for everyday meals. Sweet preparations highlight urad dal's versatility in , such as halwa—a made by roasting ground urad dal in and mixing with sugar and nuts—or laddus, ball-shaped confections rolled from roasted dal flour, commonly enjoyed during and other celebrations in southern and . Modern adaptations extend its use globally, with urad dal flour incorporated into baked goods like biscuits, cookies, and doughnuts for added , or sprouts added to salads and sandwiches for fresh, earthy flavor. These innovations also appear in vegan products, such as bean-based patties mimicking burgers, leveraging urad dal's binding properties in gluten-free formulations.

Nutritional and Health Aspects

Nutrient Composition

Vigna mungo, commonly known as black gram, offers a nutrient-dense profile that contributes significantly to dietary intake, particularly in plant-based diets. Per 100 g of dry seeds, it provides 341 kcal of , making it an efficient source for sustenance. The macronutrient includes 25 g of protein, 59 g of carbohydrates (of which 18 g is ), and 1.6 g of total fat, supporting needs while promoting through its high fiber content. Key micronutrients in dry black gram seeds are abundant, with 625 μg of aiding cellular function, 7.6 mg of iron for oxygen transport, and 267 mg of magnesium for enzymatic reactions. Additional essential minerals include 1243 mg of for electrolyte balance and 379 mg of for bone health. These values highlight black gram's role as a mineral-rich , though actual intake varies with preparation methods. Anti-nutritional factors like phytates and can reduce of minerals such as iron and , but processing methods like soaking and cooking mitigate these effects. The following table summarizes the primary nutrient composition per 100 g of dry seeds:
NutrientAmountUnit
Energy341kcal
25g
Carbohydrates59g
18g
Total 1.6g
625μg
Iron7.6mg
Magnesium267mg
1243mg
379mg
(Data from USDA; values may vary slightly by variety, with protein typically 24-26 g, carbohydrates ~59-60 g, fat ~1.3-1.6 g, iron ~7.6-8.7 mg, ~345-379 mg.) Black gram seeds contain bioactive compounds such as polyphenols and , which contribute to their properties, primarily concentrated in the seed coat. The protein is considered complete, as it includes all nine essential , though in proportions that complement grains for improved balance in diets. Nutrient levels vary by processing form; whole black gram retains higher (up to 18 g per 100 g) compared to dehusked split dal (typically 11-12 g), due to the intact coat. enhances of nutrients through enzymatic activation during and can increase content initially compared to dry . In comparison to common staples like , black gram delivers denser protein (25 g vs. 7 g per 100 g dry weight), enhancing nutritional complementarity in mixed meals. Its low of 43 supports stable blood glucose levels, attributed to the high and complex carbohydrate structure.

Potential Benefits

Vigna mungo, commonly known as black gram, contributes to digestive health primarily through its high content, which facilitates bowel regularity and alleviates by increasing stool bulk and promoting . The oligosaccharides in its seed coats exhibit prebiotic effects, selectively stimulating the growth of beneficial such as and species while resisting digestion in the upper . In terms of cardiovascular and metabolic benefits, the soluble fiber in black gram binds to bile acids, thereby reducing (LDL) cholesterol levels and supporting heart health. Its low (approximately 43) slows absorption, aiding and making it suitable for managing . Additionally, the iron content (around 7.57 mg per 100 g) helps prevent by supporting synthesis, particularly in populations with marginal iron intake. Other potential benefits include activity from and in the seed extracts, which protect against by scavenging free radicals and reducing cellular damage. The high-quality protein (about 25 g per 100 g) provides essential for muscle repair and maintenance, while (625 µg per 100 g) supports development and overall during . Recent research underscores these effects; a 2024 review highlighted hypoglycemic properties in diabetic models through improved insulin sensitivity from seed extracts. Similarly, 2024 studies on black gram extracts demonstrated activity by inhibiting pro-inflammatory cytokines, suggesting therapeutic potential for inflammatory conditions.

Varieties and Genetics

Cultivated Varieties

Vigna mungo cultivars are bred primarily for enhanced yield, disease , and adaptability to diverse growing conditions across . These varieties exhibit variations in growth habit, seed characteristics, and maturity duration, enabling in both rainfed and irrigated systems. Selection emphasizes traits that maximize while minimizing environmental stresses. In , Type 9 is a widely adopted high-yielding , achieving 10-12 quintals per under optimal conditions and demonstrating moderate suitable for rainfed areas. Pant U-19, released by Govind Ballabh Pant University of Agriculture and , is valued for its to mungbean yellow mosaic India virus (MYMIV), ensuring stable performance across varying environments with good yield potential. CO 5, developed by , is a short-duration variety maturing in 75 days, ideal for rice-fallow sequences, with yields of 8-10 quintals per and black seeds. Internationally, Mash 1008 from features bold black seeds (6-7 per pod), matures in 73 days, and offers MYMIV resistance alongside yields of approximately 10 quintals per , making it suitable for and summer sowing. In , BARI Mash-3 is a high-yielding adapted to local conditions, maturing in 70-75 days with erect growth habit and tolerance to MYMV, though specific yield data varies by location. Key traits among cultivated varieties include growth habit, with determinate types ceasing vegetative growth post-flowering for easier and indeterminate types allowing prolonged branching for higher pod set. MYMIV resistance is prioritized in selections like Pant U-19 and Mash 1008 to counter viral threats that can reduce yields by up to 80%. Seed color variations range from the typical shiny black in var. mungo to greenish in var. viridis, influencing market preferences and processing qualities. Breeding programs apply selection criteria focused on yield potential (e.g., 8-12 quintals per ), short maturity periods (65-80 days) to fit , and pod length (5-8 cm) to increase seed number per pod, thereby enhancing overall productivity. Recent breeding efforts incorporate traits like improved and heat tolerance for sustainable cultivation amid changing conditions.

Breeding and Research

Breeding programs for Vigna mungo primarily aim to enhance yield through exploiting hybrid vigor, which can increase productivity by up to 20% in selected crosses, alongside improving resistance to major diseases such as mungbean yellow mosaic India virus (MYMIV) using to introgress resistant genes from wild relatives. Efforts also target by selecting genotypes that maintain physiological stability under water stress, as demonstrated in field trials where primed seeds showed reduced yield losses compared to non-treated controls. Conventional breeding techniques, including hybridization and with gamma rays or (EMS), have been employed to generate variability for yield-related traits and stress resistance, resulting in the release of improved varieties with enhanced pod and seed characteristics. Genomic tools like CRISPR/Cas9 have emerged for precise gene editing, with trials in including species targeting traits such as flowering time and viral resistance through activation systems and pathogen genome modifications. Recent research in 2025 has incorporated for early detection of leaf diseases, with models achieving over 95% accuracy in identifying symptoms like yellow mosaic on V. mungo leaves using image datasets. Artificial neural network (ANN) models have been developed for variety identification based on and properties, attaining R² values of 0.97–0.99 for accuracy across cultivars. Rhizobium inoculation studies reported yield increases of 15–20% through improved nodulation and , particularly when combined with phosphorus-solubilizing bacteria. Conservation efforts emphasize maintaining from wild relatives to broaden the narrow base of cultivated V. mungo, with collections supporting for adaptive . Genome-wide association studies (GWAS) have identified quantitative trait loci (QTLs) associated with hardseededness and pod shattering, enabling marker-based selection to reduce pre-harvest losses while preserving desirable .

Other Applications

Medicinal Uses

In traditional Ayurvedic medicine, Vigna mungo, known as , is valued for its ability to balance Vata dosha and alleviate associated disorders, including , neuropathy, and joint degeneration by lubricating joints and supporting muscular health. It is also employed to treat dyspepsia and through its stool-bulking and moistening properties that facilitate bowel movement, while the seeds act as a to soothe urinary tract issues. Pharmacological studies have substantiated several therapeutic effects of V. mungo. and other bioactive compounds in the plant exhibit activity by modulating inflammatory pathways and . Hepatoprotective effects have been demonstrated in models of acetaminophen-induced liver damage, where seed extracts reduced markers of hepatic injury. Recent antidiabetic research, including 2024 investigations, shows that ethanolic and aqueous extracts lower blood glucose levels in diabetic animal models by inhibiting α-amylase and enhancing insulin sensitivity. Common preparations include decoctions of the seeds used for managing due to their and digestive properties, and medicated oils derived from the plant applied topically for conditions and joint . The recommended dosage for powdered seeds in Ayurvedic practice is 3-6 grams per day, typically taken with warm milk or water to enhance absorption and efficacy. V. mungo is for medicinal use, with studies in showing no or adverse effects at doses up to 2000 mg/kg body weight over 14 days. However, its moderate content (approximately 222 mg per 100 grams of dry seeds) warrants caution in individuals with or , as it may contribute to elevated levels. No major toxicities have been reported in therapeutic applications.

Non-Food Uses

_Vigna mungo serves as an important crop in agriculture, enhancing fertility through symbiotic with bacteria, which contributes to improved levels. The plant's residues, when incorporated into the , add and support nutrient in legume-based rotations. Additionally, the leaves and pods of Vigna mungo provide valuable for , acting as a high-protein that can replace conventional feeds like wheat bran in cow rations without compromising production. This utilization promotes efficient resource use in systems. Seed flour, rich in , is occasionally used as a substitute. In industrial applications, the gum extracted from Vigna mungo seeds functions as a natural in pharmaceuticals, offering sustainable options for controlled through microbeads that enable precise release mechanisms. Recent studies from have demonstrated its efficacy in formulating eco-friendly excipients for therapeutic matrices. Furthermore, starches derived from black gram exhibit notable properties, with gel adhesiveness ranging from 4.6 to 82.3 g·s, making them suitable for use in adhesives and related materials. Crop residues also hold potential for production, as plant waste can be processed into heterogeneous catalysts for generation from mixed oil feedstocks. Environmentally, Vigna mungo functions as a to mitigate , leveraging its deep and dense foliage to stabilize soil surfaces and reduce runoff in vulnerable areas. It is commonly integrated into systems, such as with or , to foster sustainable farming by optimizing land productivity, enhancing nutrient uptake, and minimizing resource competition. These practices contribute to long-term and resilience.