Inheritance of submergence tolerance in rice (Oryza sativa L.) was investigated in an 8×8 diallel cross. Duration to 50% mortality of the diallel populations (F1's + parents) under completely submerged conditions at the seedling stage was used to characterize submergence tolerance instead of the usual submergence survival percentages.
A strong prepotency of parents was found in transmitting the character to their offspring. Additive and nonadditive gene effects were highly significant. Parents highly tolerant to submergence also had high gca effects, and F1's between two tolerant parents were found to be the most tolerant of the diallel combinations. A high narrow-sense heritability was also observed.
The additive-dominance model was found valid for this diallel cross. Submergence tolerance was partially dominant over susceptibility and recessive alleles were more concentrated in the susceptible parents IR42 and IR11288-B-B-69-1.