Nutritional and agronomic potential of minor millets: A sustainable approach

Introduction

Minor millets are a group of small-seeded cereal crops that belong to the grass family Poaceae. They are termed "minor" primarily due to their lower global production compared to major cereals like rice, wheat, and maize. Despite this classification, they hold significant nutritional, ecological, and cultural importance, particularly in semi-arid and rain-fed regions where they thrive. The United Nations General at its 75 th session in March 2021 declared 2023 the International Year Millets (IYM 2023). FAO is the lead agency for celebrating the year in collaboration with other relevant stakeholders (Hay et al., 2013) [7] . Millets can grow on arid lands with minimal inputs and resilient to change climate. The theme of international year of millets is "Heathy Millets, Heathy People". Millets are an important source of nutrition and offer a range of health benefits. They are high in fiber which helps promote digestion and lowers cholesterol. Minor millets have ancient origins, with evidence of their cultivation dating back thousands of years. Minor millets hold significant cultural and culinary importance in various regions across the world (Porwal et al., 2023) [16] . Archaeological findings suggest that millets such as foxtail millet and proso millet were cultivated in China and other parts of Asia as early as 10,000 years ago, contributing to the development of settled agricultural societies (Sameer et al., 2019) [18] . Over millennia, minor millets spread across Asia, Africa, and parts of Europe through trade, migration, and agricultural diffusion (Miller et al., 2016) [13] . They adapted to diverse climatic and soil conditions, becoming integral to local farming systems. India is the major producer of minor millets such as finger millet (ragi), foxtail millet, and little millet. States like Karnataka, Tamil Nadu, and Andhra Pradesh are known for their extensive cultivation of these crops (Maitra et al., 2022) [11] . In China, cultivation of foxtail millet and proso millet, primarily in northern and northeastern regions can be seen. In Southeast Asia, minor millets like little millet are cultivated in countries such as Thailand, Myanmar, and Vietnam and in Eastern Africa; finger millet is a staple crop in countries like Uganda, Kenya, and Tanzania, where it is grown in highland regions. In Western Africa; millets such as pearl millet and sorghum dominate, but minor millets like fonio are cultivated in countries like Mali and Burkina Faso. In Southern Africa; minor millets like finger millet are grown in countries such as Malawi and Zimbabwe, contributing to food security in marginal areas. In South America; minor millets are cultivated in countries like Brazil and Argentina, particularly by indigenous communities, where they play a role in traditional diets and cultural practices (Fuller and Castillo et al., 2022) [5] . Minor millets are valued for their resilience to adverse growing conditions such as drought and poor soil fertility. They play a crucial role in food security and sustainable agriculture, particularly in regions susceptible to climate variability. Additionally, these millets are rich in essential nutrients like dietary fiber, proteins, vitamins, and minerals, contributing significantly to balanced diets and nutritional security (Singh et al., 2022) [20] .

Nutritional composition of miner millets

Minor millets are nutritionally dense grains that offer a range of essential nutrients. Minor millets are rich sources of protein, ranging from 7% to 12% by dry weight, depending on the variety and growing conditions (Amadou and Gounga et al., 2013) [1] . For instance, finger millet (ragi) contains about 7.3-7.8% protein on a dry weight basis (Mane K, Kadam et al., 2021) [12] . They provide complex carbohydrates, contributing to sustained energy release. Carbohydrate content varies from 60% to 75% of the grain's dry weight. They provide complex carbohydrates that are slowly digested, aiding in sustained energy release. Foxtail millet, for example, is composed mainly of carbohydrates (67-73%). Minor millets are rich in dietary fiber, promoting digestive health and satiety. Barnyard millet has been reported to contain approximately 12-15% fiber. Minor millets are excellent sources of dietary fibre, with levels ranging from 2% to 12% depending on the variety. Fiber content contributes to digestive health and can aid in managing cholesterol levels. They are rich sources of essential minerals such as iron, calcium, magnesium, phosphorus, and potassium, which are vital for various physiological functions (Kaur and Singh et al., 2023) [7] . Minor millets contain vitamins such as B-complex vitamins (B1, B2, B3 and B6) and vitamin E, contributing to overall health and wellbeing. Some millets contain antioxidants like phenolic compounds, which help protect cells from oxidative stress. Foxtail millet has been found to have significant antioxidant activity. They contain various vitamins, particularly B vitamins important for energy metabolism and nerve function. Foxtail millet is known to be a good source of niacin (B3) and pyridoxine (B6). Minor millets are rich in minerals such as calcium, iron, magnesium, and zinc. Finger millet, for instance, is notably high in calcium (344 mg/100 g) and iron (3.9 mg/100 g). (Tripathi and Patel et al., 2023) [24] .

Nutritional Highlights overview

• Foxtail Millet: High in carbohydrates and dietary fiber; contains significant protein. [17] .

Cultural and culinary significance of minor millets Cultural Significance

Traditional Diets: Minor millets have been integral to the diets of many indigenous communities and rural populations for centuries. They are often considered sacred or auspicious and are used in religious rituals and ceremonies.

Cultural Festivals: In regions like South Asia, millets such as finger millet (ragi) are central to cultural festivals and traditional cuisines, symbolizing heritage and community identity. Minor millets have deep-rooted cultural significance in many societies. They are often associated with rituals, festivals, and ceremonies, symbolizing fertility, prosperity, and communal harmony. For example, finger millet (ragi) is central to the cultural practices of several ethnic groups in India, where it is used in religious offerings, traditional foods, and celebrations.

Dietary Diversity

Minor millets have enriched dietary diversity in regions where they are cultivated. They provide alternatives to major cereals and contribute to a balanced diet due to their rich nutritional profile. Different millets are used in various culinary preparations, from porridges and bread to fermented foods and desserts, reflecting local tastes and preferences. (Tripathi and Vyas et al., 2023) [24] .

Traditional Knowledge and Farming Practices

Cultivation and processing techniques of minor millets have been passed down through generations, embodying traditional ecological knowledge (TEK) and sustainable agricultural practices. Farmers have developed indigenous methods for soil fertility management, pest control, and water conservation specific to millet cultivation. (Yadav and Singh et al., 2023) [7] .

• Community Resilience: Minor millets have historically served as a buffer against food insecurity and environmental fluctuations. Their ability to thrive in marginal lands and withstand droughts contributes to community resilience in times of adversity. They have been lifelines during periods of famine and scarcity, providing sustenance and nutritional security to vulnerable populations. (Ashoka et al., 2023) [3] . • Food Security: Minor millets play a crucial role in food security, especially in regions prone to climatic variability and where they serve as reliable sources of nutrition for rural communities. (Mehta et al., 2024) [4] . • Cultural Importance: They are integral to local cuisines and cultural practices, often featuring prominently in festivals, ceremonies, and traditional rituals. • Livelihoods: Cultivation of minor millets supports livelihoods of smallholder farmers, providing income and employment opportunities, particularly in marginalized and rural areas. (Mehta et al., 2024) [4] . [14] .

Culinary significance of minor millets

Health Benefits of minor millets

Millets are recognized for their high nutritional value, contributing to health benefits such as improved digestion, management of diabetes, and enhanced immunity. [22] . 5. Diabetes Management: Millets have a low glycemic index, helping in better blood sugar control and management of diabetes (Jacob et al., 2024) [8] . 6. Nutritional Security: In regions where millets are staple foods, they contribute significantly to nutritional security by providing essential nutrients that are often lacking in diets based on refined grains.

Cultural practices of minor millets

The agro-climatic requirements of minor millets vary depending on the specific type of millet and its adaptation to different environmental conditions.

Finger Millet (Ragi)

• Scientific Name: Eleusine coracana • Regions: Widely cultivated in Africa and South Asia, particularly in India, Uganda, Kenya, and Ethiopia. • Characteristics: Known for its small reddish-brown seeds and high nutritional content. It is rich in calcium, iron, dietary fiber, and essential amino acids. • Culinary Uses: Used to make porridges, malted beverages, flatbreads (roti), and fermented foods like idli and dosa in South India. • Health Benefits: Helps in managing diabetes, aids in weight loss, and is beneficial for bone health. • Temperature: Finger millet grows well in a range of temperatures but prefers moderate temperatures around 20-30°C during its growth stages. • Rainfall: It is suitable for regions receiving 600-1000 mm of annual rainfall, although it can tolerate lower rainfall conditions due to its drought tolerance. • Altitude: Grows at altitudes ranging from sea level to 2000 meters above sea level, making it adaptable to varying elevations.

Foxtail Millet

• Scientific Name: Setaria italica • Regions: Originated in China and widely grown in India, China, Japan, Korea, and other parts of Asia. • Characteristics: Small, yellowish seeds arranged in compact, cylindrical spikes. Known for its drought tolerance and short growing season. • Culinary Uses: Used in porridges, upma (a savory dish), pulao, and as a rice substitute in various cuisines.

• Health Benefits: Gluten-free, rich in carbohydrates, dietary fiber, and essential minerals like iron and magnesium.

Traditional Cultivation Methods

• Seed Selection and Saving: Farmers traditionally select seeds from the best-performing plants each harvest. This practice helps maintain local landraces adapted to specific agro-climatic conditions (Tonapi et al., 2015) [23] . • Crop Rotation and Intercropping: Millets are often grown in rotation with other crops such as legumes or tubers to maintain soil fertility and manage pests and diseases naturally. • Water Management: Traditional methods such as contour bunding, mulching, and rainwater harvesting are used to conserve soil moisture and manage water resources efficiently. • Pest and Disease Management: Traditional farmers often rely on crop diversity and natural pest predators to control pests and diseases rather than synthetic pesticides.

Cropping Systems

• Rotation: In traditional farming systems, minor millets are often part of crop rotation cycles that include legumes or other cereals, helping to maintain soil fertility and pest management. • Inter-cropping: In some regions, minor millets are intercropped with legumes or vegetables to optimize land use and enhance nutritional diversity.

Propagation and Harvesting

• Seeding: Minor millets are usually propagated through seeds, which are sown directly into the soil either by broadcasting or in rows, depending on local practices. • Harvesting: Harvesting methods vary but typically involve cutting the mature plants and threshing the grains to separate them from the chaff. Traditional methods like hand harvesting and threshing are still prevalent in many regions.

Modern Cultivation Methods 1. Improved Varieties and Hybridization

Modern Approach: Modern agriculture incorporates improved varieties through breeding programs and hybridization to enhance yield potential, disease resistance, and nutritional quality.

Mechanization and Precision Farming

Modern Approach: Mechanization of planting, irrigation, and harvesting processes increases efficiency and reduces labour dependency. Precision farming techniques optimize inputs such as water and fertilizers.

Synthetic Inputs Modern Approach:

The use of synthetic fertilizers, pesticides, and herbicides is common in modern agriculture to maximize yield and manage pests and diseases effectively.

Irrigation Practices

Modern Approach: Modern cultivation often relies on irrigation systems such as drip irrigation and sprinklers to ensure consistent water supply, especially in regions with erratic rainfall.

Comparative Analysis

• Benefits of Traditional Methods: Traditional cultivation methods promote biodiversity, maintain soil health, and preserve local agricultural knowledge and practices. • Benefits of Modern Methods: Modern techniques can increase productivity, improve crop resilience to climate change, and reduce labour intensity, meeting the demands of growing populations.

Role in sustainable agriculture and climate resilience of minor millets

Minor millets play a crucial role in sustainable agriculture and climate resilience due to their inherent characteristics and cultivation practices.

Role in Sustainable Agriculture 1. Biodiversity Preservation Diverse Genetic Resources

Minor millets contribute to agricultural biodiversity by preserving a wide range of genetic resources adapted to various agro-climatic conditions.

Soil Health and Fertility

Crop Rotation: Traditional cultivation practices of millets involve crop rotation with legumes and other crops, which enhances soil fertility and reduces the dependence on synthetic fertilizers.

Water Use Efficiency

Drought Tolerance: Minor millets, such as finger millet and pearl millet, are known for their drought tolerance, requiring less water compared to major cereals like rice and wheat. [6] .

Climate

• Market Access: Limited market demand and low prices relative to major cereals pose challenges for farmers. [21] .

Conclusion

References

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