In order to determine the gene action and heritability of some quality characters in rice varieties, five pure lines of rice (IR28, Gil3, Sangjo, Gharib, Domsiah) were crossed in an incomplete diallele mating manner. The characters including amilose content, gelatinzation temperature and gel consistency in rice kernel (parents as well as F1) were analyzed using a randomized block design with three replications. The results of analysis of variance indicated significant differences among studied genotypes. Because of the failure of the Hayman hypothesis, diallele analysis for gelatinzation temperature was not performed .Genetic analysis of amilose content indicated the greater role of additive gene action to the dominant gene action. Further more, high narrow sense heritability of the mentioned character enables the breeder in direct selection to increase the genetic advance. For gel consistency the role of dominant gene action was more than that of additive gene action. Therefore, for this character direct selection strategy is ineffective, being important only for production of F1 hybrid varieties.
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