Humans require more than 20 mineral elements for healthy body function. Calcium (Ca), one of the essential macro-mineral, is required in relatively large quantities in the diet for maintaining a sound overall health. Despite the importance of adequate Ca intake, the World Health Organisation (WHO) estimates that low dietary intake of Ca is common across the world (WHO, 2006). It has recently been determined (mainly based on food supply) that 3.5 billion people were at the risk of Ca deficiency in 2011, with approximately 90% of the affected individuals in Africa and Asia (Kumssa et al., 2015). Young children, pregnant and nursing women in marginalized and poorest regions of the world, are at highest risk of Ca malnutrition. Elderly population is another group of people most commonly affected by Ca deficiency mainly in the form of osteoporosis and osteopenia.
Improved dietary intake of Ca may be the most cost-effective way to meet such deficiencies. As large segments of these populations are typically dependent on what they grow and produce for their Ca need, staple crops that can offer adequate Ca requirements, especially for people of low income groups, offer an excellent and sustainable solution. Among all cultivated cereals, finger millet [Eleusine coracana (L.) Gaertn.], an annual small millet of Africa and Asia, has the highest concentration of Ca (350mg/100g) in its grains and can serve as an excellent sustainable candidate for Ca biofortification. It has three times more Ca than milk and 10-fold higher Ca than brown rice, wheat or maize (Kumar et al., 2016a). Besides Ca, finger millet is also very rich source of iron, amino acids like methionine, slowly digestible starch and phytochemicals like polyphenols. It is a gluten-free, low fat cereal which is non-allergic and easily digestible. Apart from its nutritional attributes, finger millet has excellent environmental sustainability credentials. It can easily withstand harsh climatic conditions, low soil fertility, requires very little inputs with a short growing season (Kumar et al., 2016a). It can reach the yield potential of up to 10 tons/ha under optimum irrigated conditions (Padulosi et al., 2015). It has excellent storage quality traits and can be valuable in areas where farmers suffer losses due to dearth of post-harvest management. For these characteristics, it is often termed as a “super cereal” (Kumar et al., 2016a). Therefore, a better understanding of the genetic basis of grain Ca accumulation in finger millet will offer an improved strategy for Ca biofortification breeding programs. However, so far limited genetic and genomic studies have been conducted in finger millet.
