Biofortified Maize for Nutritional Security
Micronutrients such as vitamins, amino acids and minerals are required in minor quantities but are essential for normal growth and development of humans. Since human body cannot synthesize many of these micronutrients, these are to be provided through dietary means. Foods deficient in such micronutrients leads to ‘malnutrition’ – popularly phrased as ‘hidden hunger’. It affects nearly 88 percent of the countries that suffer from two or three forms of malnutrition. Worldwide, an estimated two billion people suffer from micronutrient deficiency, while 815 million people are undernourished. 155 million children under the age of five are stunted, while 52 million do not weigh enough according to height (wasting). Nearly 45 percent of deaths among children under age five are linked to malnutrition. In India, 21.9 percent of the population lives in poverty, and therefore they are vulnerable to various health problems. 38.4 percent of children (<5 years) in India are stunted, while 21 percent and 35.7 percent are wasted and under weight, respectively. Malnutrition contributes to global burden of disease, and loss in annual gross domestic product (GDP) in Asia and Africa to an extent of 11 percent. Considering its wide spread ramification, the global community set ‘Sustainable Development Goals’ (SDGs) for sustainable development where improved nutrition being the platform for progress in health, education, employment, female empowerment, and poverty. It has been estimated that alleviating malnutrition is one of the most cost-effective steps with every $1 invested in a proven nutrition programme offers benefits worth $16.
Diverse Strategies to Alleviate Malnutrition
Fortification: Here, micronutrients are artificially added with food. One of the best examples is iodized salt, where a required quantity of iodine is consumed along with the salt. Wheat flour double-fortified with iron and folate is also used in many countries. Niacin fortified bread to overcome pellagra is another such example.
Supplementation: Here, micronutrients are provided in the form of pills. One of the best examples is vitamin-A pills that are distributed in the targeted area. Calcium tablets and protein powders are other examples.
Dietary Diversification: Here, naturally available diverse foods are consumed to provide balanced nutrition.
Biofortification: Crop inherently rich in bio available micronutrients is developed through breeding strategies. It is possible to increase a specific or combination of nutrient(s) by breeding, once sufficient genetic diversity exists in germplasm.
Among these, fortification, supplementation and dietary diversification in general have not been found viable in the long run due to various reasons. Lack of purchasing power of the poor due to poverty, restricts the access to fortified foods, thereby reducing their efficiency and application. Poor infrastructure in developing countries has limited the widespread use of direct supplementation. Diet diversification is often limited by crop seasonality, expense and lack of purchasing power by the poor. Biofortification on the other hand is regarded as the most sustainable and cost effective approach. Agricultural systems so far have traditionally focussed mostly on increasing productivity. New varieties should not only provide enough calories to meet the energy needs of the poor, but also deliver all the essential nutrients needed for adequate nutritional health.
Deficiency of Micronutrients: Among various micronutrients, vitamin-A, lysine and tryptophan, are essential for human nutrition, and their deficiency leads to various symptoms and health disorders.
Vitamin-A: Vitamin-A is essentially required by humans for the normal functioning of the visual system, growth and development, maintenance of epithelial cell integrity, immune system and reproduction. An early symptom of deficiency is night blindness. Structural alterations of the conjunctiva and cornea such as xerophthalmia and keratomalacia may follow, and subsequent inflammation and infection result in irreversible blindness. It also results in predisposition of several diseases like anaemia, diarrhoea, measles, malaria and respiratory infections.
Lysine: It serves as a building block in protein synthesis besides serving as precursors for several neuro-transmitters and metabolic regulators. The deficiency of lysine leads to fatigue, dizziness, nausea, anemia, delayed growth, loss of appetite and reproductive tissue.
Tryptophan: It is also a building block of proteins, and serves as precursors for several neuro-transmitters and regulators of metabolic pathways. Depression, anxiety, impatience weight loss and slow growth in children are the major symptoms of tryptophan deficiency.
Maize and its Importance
Maize occupies an important position in the world economy, and serves as an important source of food and feed. Together with rice and wheat, it provides at least 30 percent of the food calories to more than 4.5 billion people in 94 developing countries. In India, maize is the third most important cereal after rice and wheat. It is cultivated in an area of >9.0 million hectare with production of 22.57 million tonnes. The demand for cereals will continue to increase as a consequence of the expanding human population. The world will have around 7.7 billion people by 2020, and it will reach up to 9.3 billion by 2050, and the demand for maize between now and 2050 will double in the developing world. By 2025, India too would require double the production (50 million tonnes) of maize grain to meet the domestic demand. In India, maize grains are consumed as food in the form of flat bread (chapatti), different forms of porridges, boiled and roasted forms. However, traditional maize is deficient in vitamin-A, lysine and tryptophan, and therefore warrants urgent attention. Biofortified maize hybrids coupled with high grain yield potential have now been developed at ICAR-Indian Agricultural Research Institute, New Delhi through molecular breeding approaches. These hybrids possess natural variants of the target genes available in germplasm.
Provitamin-A rich maize: Traditional yellow/ orange maize possesses very low provitamin-A (1-2 ppm), although it is rich in other carotenoids that do not function as precursor for vitamin-A synthesis in human body. By selecting a natural mutant of crtRB1 gene, IARI has developed country’s first provitamin-A rich maize hybrid.
Pusa Vivek QPM9 Improved: It is an early maturing hybrid and possesses high provitamin-A (8.15 ppm). It also contains high tryptophan (0.74 percent) and lysine (2.67 percent) in protein, and thus is a multi-nutrient maize hybrid as well. It has been released and notified for Northern Hill Zone [Jammu & Kashmir, Himachal Pradesh, Uttarakhand (Hills) & North Eastern states] and Peninsular Zone [Maharashtra, Karnataka, Andhra Pradesh, Telangana & Tamil Nadu]. Its average grain yield is 5588 kg/ha (NHZ) and 5916 kg/ha (PZ), with a potential grain yield of 7968 kg/ha (NHZ) and 9368 kg/ha (PZ).
Quality protein maize (QPM): Normal maize contains low levels of lysine (2.0-2.5 percent) and tryptophan (0.3-0.4 percent) in endosperm protein. By selecting a natural variant of a gene, called ‘opaque2’, IARI developed three QPM hybrids that possess enhanced protein quality due to elevated level of lysine and tryptophan.
a. Pusa HM4 Improved: It is a medium maturing hybrid that possesses high tryptophan (0.91%) and lysine (3.62%) in protein. It has been released and notified for North Western Plain Zone [Punjab, Haryana, Delhi, Uttarakhand (plains) & western Uttar Pradesh]. Its average grain yield is 6419 kg/ha, with a potential grain yield of 8568 kg/ha.
b. Pusa HM8 Improved: It is a medium maturing hybrid that possesses high tryptophan (1.06%) and lysine (4.18%) in protein. It has been released and notified for Peninsular Zone [Maharashtra, Karnataka, Andhra Pradesh, Telangana & Tamil Nadu]. It’s average grain yield is 6258 kg/ha, with a potential grain yield of 9261 kg/ha.
c. Pusa HM9 Improved: It is a medium maturing hybrid that possesses high tryptophan (0.68%) and lysine (2.97%) in protein. It has been released and notified for North Eastern Plain Zone [Bihar, Jharkhand, Odisha, West Bengal, & Eastern Uttar Pradesh]. Its average grain yield is 5201 kg/ha, with a potential grain yield of 7408 kg/ha.
Apart from these, several QPM hybrids viz. Shaktiman-1, Shaktiman-2, Shaktiman-3, Shaktiman-4, Shaktiman-5, HQPM-1, HQPM-4, HQPM-5, HQPM-7, Vivek QPM-9, Pratap QPM Hybrid-1 developed by SAUs and other ICAR institute are also available for commercial cultivation in the country.
Dependence on cereals also makes the diet deficient in proteins especially among resource-poor people. During 2016, protein energy malnutrition (PEM) has been the leading cause of human deaths among nutritional deficiencies. Maize protein rich in lysine and tryptophan possess higher quality, and helps combating PEM. Nutritional benefits of QPM on infants and children are well demonstrated. Consumption of maize grains with enhanced provitamin-A provides much balanced nutrition to humans. Chickens fed with provitamin-A rich maize grains lay eggs that accumulate more vitamin-A in yolk, thus making it more nutritious.
Recently unveiled National Nutrition Strategy - 2017 by NITI Aayog, Govt. of India envisages alleviation of malnutrition in the country through food based solutions. Development of biofortified crops with enhanced micronutrients has been a major focus area of Indian Council of Agricultural Research (ICAR), the premier organization of agricultural research in the country. To further expedite the process of development of biofortified crops, ICAR has recently funded a Consortia Research Platform on ‘Biofortification in Selected Crops for Nutritional Security’, where rice, wheat, maize, pearl millet, sorghum and minor millets have been targeted for nutritional enrichment. Department of Biotechnology, Govt. of India has also funded several programmes on enhancement of nutrition in crops. Apart from maize, several varieties of biofortified cereals viz., rice (protein rich ‘CR Dhan 310’, zinc rich ‘DRR Dhan 45’), wheat (iron and zinc rich ‘WB-02’ and ‘HPBW-01’) and pearl millet (iron and zinc rich ‘HHB-299’, and iron rich ‘AHB-1200’) have now been developed through targeted breeding approaches. Inclusion of these biofortified cereals in different Government sponsored programmes like National Food Security Mission (NFSM), Rashtriya Krishi Vikas Yojna (RKVY) as well as nutrition intervention programme like Integrated Child Development Services (ICDS) scheme, ‘Mid-day meal’ and Nutrition Education & Training through Community Food & Nutrition Extension Units (CFNEUS) would help in providing the much needed balanced food to poor people. These biofortified cereals are high yielding, and besides serving as an important source for livelihood to poor people they assume great significance in nutritional security.
* Vignesh Muthusamy and Rajkumar Uttamrao Zunjare, Division of Genetics, ICAR-Indian Agricultural Research Institute (IARI), New Delhi; Contact: firstname.lastname@example.org