Osmolyte-induced water deficit stress mitigation during panicle initiation stage in transplanted rice (Oryza sativa L.)

A field experiment was conducted to observe the osmolyte-induced water deficit stress mitigation during the panicle initiation stage in transplanted rice (Oryza sativa L. cv. BRRI dhan72). At the panicle initiation stage, plants were simulated with four levels of water regimes viz., well-irrigated (D-0), water deficit for 5 d (D-1), 10 d (D-2) and 15 d (D-3). Plants were treated with or without 10 mM of proline (Pro) and trehalose (Tre) as foliar spray started at mid-vegetative stage and continued till the end of stress period. Results revealed that water deficit stress drastically reduced most of the plant morpho-physiological attributes while other yield contributing characters were also affected due to prolonged water deficit stress. However, exogenous application of osmolytes like Pro and Tre significantly increased all those morphological, physiological and yield contributing parameters. Foliar addition of osmolytes concomitantly decreased the number of non-effective tillers and the number of unfilled grain panicle(-1) under water stress condition. Although both the osmolytes performed well under multiple duration of drought stress, the application of 10 mM Pro markedly improved all growth and yield contributing parameters under D-1 water deficit stress compared to other stress durations. Hence, it may be concluded that the use of osmolytes would be a prospective remedy against moderate water deficit stress in transplanted rice production.