The objective of this work was to develop the use of backcrosses among elite parental lines and to identify the parents with higher probability of developing superior progenies when used in crossing blocks. The following traits were analyzed: number of panicles per plant and plant grain yield in kg. ha-1. Five oat genotypes (UPF 16, UPF 18, UFRGS 7, UFRGS 17 and URPel 95/015) were crossed on a diallel design not considering reciprocal crosses. F1 populations were obtained from the cross of parental lines. These populations were either backcrossed to obtain the populations BC1P1, BC1P2, BC1P1F2, BC1P2F2, BC2P1 and BC2P2, or selfed to obtain F2 and F3 generations. The F1 hybrids, the F3 populations and the backcrosses were field evaluated during a 2003 winter season. A cross dependent superiority was observed for backcrosses, when compared to the F3 population. An improvement in progeny superiority was observed when the background was increased for the genotypes UPF 16, UFRGS 7 and UFRGS 17. These results were observed in 75% of the crosses, in which those genotypes were present as parental lines UPF 18 and URPEL 95/015 presented less favorable genes to increase grain yield, showing a tendency to reduce the performance of progenies when of their genetic background was increased in the tested combinations.
backcross; diallel; grain yield
