INFLUENCE OF RECOMBINATION ON GENETIC-VAR IABILITY .1. AN EXPERIMENTAL-STUDY

In order to evaluate the possible interest for plant breeding of a gen e modifying recombination rates, an experimental study was undertaken on petunia, as in this species an allele (allele Rm1) increases recomb ination rates. The effect of this allele Rm1 on genetic variability of quantitative traits was studied. A group of 5 Rm1/rm1 plants and a gr oup of 5 rm1/rm1 plants were studied. Four morphological traits and 1 phenological trait were measured in the populations derived from the 5 plants of each group, either by generation of a circular mating desig n (SIB population), or by 1 (AF1 populations) or 2 generations (AF2 po pulations) of selfing. Within and between-family variances in these po pulations were compared within each group, and between groups for each kind of progeny. Although differences existed between SIB, AF1 and AF 2 populations within each group, no significant difference was found b etween groups for each kind of progeny. Possible reasons for the lack of differences between groups are discussed.