Abstract

Submergence stress is considered as the third most important limitation of rice production contributing to its low productivity in lowland and rainfed ecosystem. Characterization of genotypes and using them in breeding programme is likely the best option to withstand submergence and stabilize productivity in these environments. However, progress in genotypes characterization has been slow but can substantially be enhanced by using potential of biochemical and molecular markers, to enhance and speedup progress through breeding. Survival percentage, alcohol dehydrogenase (ADH) activity and isozyme profiles were carried out in this investigation. The response to submergence appears to be complex and involves a number of enzymes, therefore, cultivars were also characterized by using other isozymes (Aspartate aminotransferase, AAT; Malate dehydrogenase, MDH; Esterase, EST and Peroxidase, POX) and molecular marker like random amplified polymorphic DNA (RAPD). Dendrogram constructed, using isozymes and RAPD data clustered the rice genotypes into three major groups, submergence tolerant, moderately tolerant and susceptible. The result obtained in this study will help plant breeders in breeding high yielding cultivars for lowland eco-systems, with submergence tolerant cultivars.

Key words: Rice, submergence stress, alcohol dehydrogenase (ADH), isozyme, random amplified polymorphic DNA (RAPD), FR13A.