R ecent studies suggest that abscisic acid (ABA) at its basal level plays an important role during seed set and grain filling events. Under drought stress ABA levels were found to be significantly enhanced in the developing seed. Until now we lacked an understanding of (1) ABA homeostasis in developing seeds under terminal drought and (2) the interactive role of ABA in regulating the starch biosynthesis pathway in developing grains under terminal drought. We have recently reported the possible regulation of ABA homeostasis in source (flag leaf) and sink (developing grains) tissues under post-anthesis drought stress in barley and concluded that significantly enhanced ABA levels in developing grains are due to strong activation of the ABA deconjugation pathway and fine regulation of the ABA biosynthesisdegradation pathway.1 Additionally, we provided evidence for the role of ABA in differential regulation of starch biosynthesis genes and a significant upregulation of starch degradation beta amylase genes under drought, i.e., ABA not only influences the rate of starch accumulation but also starch quality.ABA produced under normal conditions regulate various physiological processes of plant development like flowering, seed development, synthesis of storage proteins and lipids, embryo morphogenesis, dormancy, stomatal opening and trigger senescence and remobilization.2-5 Under water stress, ABA regulates flower development directly via a fernesol kinase. 6 ABA is not only correlated with regulation of primary carbon metabolism, 7 but