Estimativas de correlacoes genotipicas a de ambiente em geracoes com elevada frequencia de heterozigotosGenotypic and enviromental correlation estimates with high heterozygous frequency

摘要

The use of genotypic correlation helps evaluating the magnitude and direction of associations between characters facilitating the application of indirect selection, leading to faster and larger genetic gains in oat (Avena saliva L.) breeding programs. This study aimed at testing a modification of PETR & FREYS' (1996) formula, to obtain genotypic, phenotypic and environmental correlation estimates through the analyses of four F-2 oat segregant populations: OR 2 x UPF 18, UPF 7 x CTC 5, OR 2 x UPF 7 and UPF 18 x CTC 5. The estimates of genetic correlations indicated that plants of superior grain productivity could be selected indirectly through the characters: number of panicles per plant, panicle weight, number of grains per panicle and average grain weight. However, the opposite direction and the difference of magnitude of correlation estimates between many pairs of characters on the four studied populations did not allow any generalization of selection strategies. This is probably due to the imposed limitations caused by the differences on the genetic background of parents and populations. In this way, it is advisable to test the combining ability of major genotypes used in artificial crossings in Brazil, to establish more effective criteria for superior genotype selection.