PLANT CELL BIOTECHNOLOGY AND MOLECULAR BIOLOGY

Moisture stress induces osmotic stress to plants, shaping crop evolution. Rice production is affected by extreme climate change which has a negative impact on global food security. In India, almost 40 per cent of rice is cultivated under rainfed condition, which is under the constant threat of erratic rainfall distribution. In the present investigation, 85 traditional rice landraces and 15 improved cultivars were screened for drought tolerance potential under In vitro condition in hydroponics. Artificial moisture stress with maximum negative osmotic potential of (-) 1.5 Mpa was induced under polyethylene glycol-treated hydroponic conditions. Screening was carried out under stress condition on 30^th day along with drought tolerant/susceptible checks IR 64 Drt 1 and IR 64 respectively for phenotypic variations.  While clustering the rice landraces based on the drought tolerance ability, seven distinct clusters formed by hierarchical agglomerative cluster analysis (HGCA). The accessions of cluster I possessing superior drought tolerance include: Chenkayama, Kuliyadichan, Rajalakshmi, Chandaikar, Oheruchitteni, Aathur kichadi samba, Ariki raavi and Sahabhagidhan along with drought tolerant check IR 64 Drt 1, represented by traits such as seed vigour, survival percentage, germination rate, germination index, root length, seedling length, root -shoot ratio (R/S) and root length. Cluster VII comprising of Anjali, Mutta karuva, Seeraga samba, Mallikar, Nootripathu, Arubathamkodai and Annada represented by R/S ratio and root length showed drought tolerance as revealed by the cluster distance. These diverse genetic materials selected can be used as an effective donor parents in future rice breeding programmes for drought tolerance.