Differential Calcium responsiveness in terms of Plant's Growth and accumulation of Nutrient-Anti nutrient in two Finger Millet Genotypes differing in grain Calcium content using a designed Circulatory Hydroponics system

Abstract

Finger millet (Eleusine coracana) commonly known as ragi is model crop of choice for variety of reasons. These include its high nutraceutical value, excellent storage qualities and most important low input crop. In this study, circulatory hydroponic system was designed and optimized to assess the nutrient responsiveness under the influence of exogenous calcium (Ca) application in finger millet. Impact of different concentrations of exogenous Ca in the form of calcium nitrate on plant's growth and nutrient-antinutrient changes were determined in grains of two contrasting genotypes GP-1 (low Ca) and GP-45 (high Ca) of finger millet. The plants were supplied regularly with different levels of Ca in Hoagland's nutrient medium. Up to 10 mM of exogenous supplied Ca concentration, the threshold potential in terms of Ca accumulation as well as different plant's growth parameters of GP-45 (high Ca) genotype was higher than GP-1 (low Ca); while at 20 mM of Ca concentration, the decline in Ca accumulation and plant's growth was observed in both the genotypes. The highest Ca accumulation was recorded in GP-45 genotype at 10 mM of Ca concentration. Interestingly, with increasing concentration of exogenous Ca, a higher oxalic acid content in grains was observed in GP-1 while higher content of tartaric acid were observed in GP-45 genotype having high grain Ca. These results revealed that Ca interacts with oxalic acid and other organic acids like tartaric acid which is genotype dependent. Hence, the interaction of Ca with antinutrient(s) might be under control of both genetic and epigenetic factor(s).