Physio-biochemical analysis reveals drought stress tolerance mechanism in Proso millet (Panicum miliaceum L.)

Proso millet (Panicum miliaceum L.) is one of the important millet crops grown in India and other parts of the world. Proso millet withstands drought by its short life cycle and high water use efficiency mechanism. During drought conditions, some of the osmolytes are accumulated in plants to acclimate the stress. To understand the drought stress response in proso millet, studies were conducted on the activities of antioxidant enzymes ascorbate peroxidase (APX) and peroxidase (POX) in addition to proline, malondialdehyde (MDA) and total soluble sugars. The drought induced plants showed elevated levels of these antioxidant enzymes and metabolites. Also, a decrease in chlorophyll content, relative water content (RWC) and chlorophyll stability index (CSI) was observed under stress conditions. Water saturation deficit showed the indirect relationship with RWC. These results provide a base for isolation and characterization of potential drought-related candidate genes or quantitative traits from proso millet. This can be further used for molecular breeding and/or engineering programs for improving abiotic stress tolerance in crops.