Effects of recombinations on variability and heritability of traits in maize populations with exotic germplasm

The following maize populations were encompassed by the study: a population with 25% of exotic germplasm (1601/5xZPL913)F2R0 and populations developed after three (1601/5xZPL913)F2R3, that is, five (1601/5xZPL913)F2R5, gene recombination cycles. The S, progeny trial was set lip according to the nested design in two replications and two locations during two years (2001 and 2002). The average values for all traits except moisture at harvest increased. The changes of mean values of yields and other traits can be very important from the aspect of long-term breeding programmes. Different agroecological conditions, genotype, family x location interaction and family x location interaction within the set signficantly affected all observed traits of populations. Genetic and phenotypic variances for all traits except the 1000-kernel weight decreased under the effects of the number of recombination cycles, which was confirmed by the coefficients of heritability. A significant decrease was not detected in yields and ear lengths, which is particularly important for practical breeding. Three cycles of gene recombination are sufficient for this population prior to the application by various breeding methods.