ESTIMATES OF GENETIC AND PHENOTYPIC PARAMETERS IN A SEGREGANT POPULATION OF RICE IRRIGATED BY CONTINUOUS FLOODING

Estimates of genetic and phenotypic parameters were obtained by using data from families of a recurrent selection program in rice. An experi ment using population CNA-IRAT 4ME/1/1 was conducted at two locations (Lambari and Cambuquira) in the State of Minas Gerais, Brazil. At Lamb ari, families S-0:2 and S0:3 were assessed during crop seasons 1992/19 93 and 1993/1994, respectively. In the Cambuquira trial, only S0:3 fam ilies were tested in 1993/1994. The experimental design was a 10 x 10 lattice with three replications. The following traits were assessed: g rain yield (GY), mean number of days to flowering (FL), plant height ( PH), and the incidence of neck blast (NB) caused by Pyricularia grisea and grain staining (GS) caused by Drechslera oryzae. This population proved to be promising for recurrent selection, as it had high average yield and genetic variability. Heritability estimates obtained using variance components were generally greater than estimates of realized heritability, and heritability obtained by parent-offspring regression .