Screening of Elite Coarse Rice Lines for Drought Stress Simulated by Polyethylene Glycol (PEG) at Seedling Stage

Abstract

Among various abiotic stresses causing serious impact on crop growth, drought poses a significant reducing stress towards crop yield and its stability over the time and locality. In terms of sensitivity to this environmental stress, rice, which is a drought-sensitive crop, exhibits notable varietal variability. for the estimation of elite coarse rice lines to withstand against the drought stress especially during early plant developmental phases and germination and seedling stage, an experiment was carried out from June to July 2021 at the Rice Molecular Breeding Laboratory of the Rice Research Program, Crop Sciences Institute, National Agricultural Research Centre, Islamabad. Ten elite coarse rice lines were subjected to varying degrees of drought stress as 0, 10, 15 and 20% through the application of Polyethylene glycol (PEG-6000). To carry out experimentation, carried out it following completely randomized design. Germination was found to be negatively associated with stress level as germination was 100% in the control and 0% in the highest stress level (20% PEG). All attributes examined were shown to differ significantly across all levels of drought stress. For treatment, traits such as germination rate, emergence percentage, vigor index, seedling height, fresh weight and dry weight of seedling are significant at 10% alpha, likewise the interaction of genotypes x treatments (G x T) is significant for seedling height at 1% alpha in all rice lines, seedling height and dry weight decreased along with elevated stress levels. Four lines, NRPC-9, NRPC-7, NRPC-6, and NRPC-1 were shown to be tolerant at 15% PEG 6000 water stress level while all lines tolerated 10% PEG induced water stress. It was concluded from our findings that elite coarse green super rice (GSR) lines viz; NRPC-9, NRPC-7, NRPC-6, and NRPC-1 are good drought tolerant and can be exploited in future breeding initiatives for variety development with increase drought stress.