ASSESSMENT OF RICE (ORYZA SATIVA L.) GENOTYPES FOR DROUGHT STRESS TOLERANCE USING MORPHO-PHYSIOLOGICAL INDICES AS A SCREENING TECHNIQUE

Drought stress is one of the primary problem for agricultural crops which causes a great decline in crop production in Pakistan and worldwide. Rice is an economically main cereal crop affected by drought stress. In this study, twenty-one rice genotypes (including 19 mutants (M5 generation) of super basmati and two varieties were subjected to various concentration of PEG-600 (10% and 15%) at seedling stage to explore the mechanism of drought stress tolerance. PEG-6000 induced drought stress caused a substantial decline in growth attributes and relative water contents (RWC), and increase the levels of electrolyte leakage (EL), hydrogen peroxide (H2O2) and malondialdehyde (MDA) in all rice genotypes. A significant difference among the tested rice genotypes based on morpho-physiological indiceswas recorded. Based on morphophysiological indices (RLSI, SLSI, PFWSI, PDWSI, EL, MDA and H2O2), genotypes HTT-119, HTT-74, HTT-92, HTT-97, HTT-104, HTT-119, HTT-125 and HTT-132 were categorized as drought tolerant, while HTT-19, HTT-39, Super basmati (Super Bas), HTT-81, and IR-64 performed poorly recognized as sensitive genotypes. In addition, remaining eight mutants were identified as moderate tolerant. According to present study findings, the screened rice genotypes for drought tolerance can also be suggested to farmers for the improved production and yield of crop on drought-affected area.