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.
