Screening Some Modern Rice Cultivars for Submergence, Drought and Salinity Stress at Seedling Stage

Abstract

Rice is grown in varied environmental conditions where it shows different levels of reaction to abiotic stresses, depending on the environmental conditions of origin and, cultivation. Drought and high salinity are the most important environmental factors that cause osmotic stress and dramatically limit plant growth and crop productivity. Submergence affects 15 million ha of low land rice growing areas in South and South East Asia. In Sri Lanka alone, rice lands with flash flooding exceed 25,000 - 40,000ha. In the present study 20 modem rice cultivars were evaluated for submergence, drought and salinity stress at seedling stage. An eperiment was carried out according to RCBD (Randomized complete block design) with four replicates and 20 plants per each replicate. Submergence, drought and salinity stresses were given separately at seedling stage and plant survival percentages were measured at the end of the experiment. Data were analyzed using SAS and correlation analysis was done for each pair of stress treatment. Findings of this study reveal the different levels of submergence, drought and salinity stress tolerances of these modem rice cultivars at seedling stage. The highest survival percentages at submergence (42%), drought (97%) and salinity (89%) stress were recorded by Bw 492, Bg 452, At 402 respectively. There is a positive correlation between drought and submergence tolerance and negative correlation between salinity and drought stress in modern rice cultivar at seedling stage.