Identification and Characterization of drought tolerant rice genotypes using physiological and biochemical traits

Abstract

Drought stress impacts over 23 million hectares of rainfed rice around the world. As a result of the current climate change, the situation is anticipated to worsen. Drought has a negative impact on agricultural growth factors, resulting in lower yields. The extent of the damage is determined by the scale of the stress, the duration of the stress, and the plant's growth stage. Changes in the rice plant's morphological, physiological, biochemical, and molecular processes reflect the negative outcomes. Thus, identification of drought-tolerant rice genotypes resilient to changing climate is need of the hour. The present study was conducted to evaluate the performance of seven rice genotypes using morphological, physiological and biochemical parameters, under induced drought (water stress) conditions at seedling level. Seedlings of all the genotypes were grown in soilless hydroponic system with ½ strength Hoagland’s solution for 21 days. Later drought stress was imposed by feeding seedlings with 20% PEG6000 in Hoagland’s solution for 7 days along with control treatment (without PEG). At the end of the stress period sampling was done to record the root and shoot lengths and various physiological parameters viz., total chlorophyll content, cell membrane stability index, relative water content were estimated. Proline and MDA content were also estimated as biochemical parameters. The results obtained from the study revealed the existence of significant variation in the seven genotypes studied for different physiological and biochemical parameters. Out of the seven genotypes studied, HT-18(AC-34973) has performed better than the tolerant check Sahbhagi Dhan and showed better root and shoot growth, maintained higher total chlorophyll content (2.6 mg/gm FW), relative water content (61.3%) and membrane stability index (52.9%), it has also shown higher proline content (20.52 μmoles/gmFW) and lesser MDA content (0.068) under stress. The present study has identified HT-18(AC-34973) as seedling level drought tolerant genotype.