| Summary: | An investigation in rice (Oryza sativa L.) was carried out by utilizing two cosmopolitan rice varieties of Tamil Nadu namely ADT 43 and Improved White Ponni along with the donor submergence tolerance FR13A to reveal the genetics and gene action for submergence tolerance. The generation mean study was done by developing six generations viz., P1, P2, F1, F2, B1 and B2 for two cross combinations namely ADT 43 × FR 13A (Cross 1), IWP × FR 13A (Cross 2).Gene action studies for submergence tolerance through generation mean analyses revealed that all the yield and yield component traits under submergence condition were mostly influenced by dominance gene action, except for number of filled grains per panicle, total number of grains per panicle and spikelet fertility in cross 1. Regarding 1000 grain weight epistatic gene action was predominant in cross 1. In cross 2, dominant gene action alone was predominant for the trait number of productive tillers per plant whereas, the epistatic gene effects were predominant for the traits number of filled grains per panicle and total number of grains per panicle. The traits, days to flowering, plant height, number of tillers per plant, spikelet fertility, 1000 grain weight and single plant yield were controlled by additive, dominance followed by epistatic gene action. The generation mean analysis also revealed that number of filled grains per panicle, 1000 grain weight and single plant yield in cross 2 under submergence condition were much influenced by different types of gene action viz., additive, dominance and epistasis with complementary epistatic interaction. These crosses would be utilized for yield improvement through single plant selection in segregating generations. To obtain desirable segregants, the appropriate breeding method would be bi-parental mating or one or two cycles of recurrent selection followed by pedigree breeding will be effective and useful method to obtain expected improvement in rice under submergence tolerance
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