ESTIMATION OF THE GENETIC-PARAMETERS IN T HE IRRIGATED RICE POPULATION CNA-IRAT-4 0/3/

The estimation of genetic parameters of a population helps to elucidat e the nature of gene action involved in the inheritance of traits and to establish the basis to choose the most appropriate breeding procedu res. The present work aimed to estimate the following parameters for t he population CNA-IRAT 4/0/3: components of genetic variance, heritabi lity, coefficient of genetic variation and variation index. The degree of association among some traits was also evaluated. Data were obtain ed from 59 self pollinated half-sib families and from 60 S-0:2,, evalu ated in Goianira, GO, Brazil, in a complete randomized block design wi th two replications. Non-additive components of genetic variance are n ot relevant for plant height, panicle length and 100 seed weight. For grain production and panicle number per plant, which show significant estimates for dominante variance, the heritability coefficients and va riation indexes are of intermediate to low magnitudes. In spite of the se two values, they may suffer substantial modifications in their aver ages due to their coefficients of genetic variation being as high as t hose of more heritable traits.