XVI International Botanical Congess

Inbreeding depression plays a primary role in the evolution of selfing. In order to determine its magnitude and possible role in polyploid organisms, approximate solutions for the mean fitness and inbreeding depression values expected in partially selfing autotetraploid populations were computed. As in diploids, purging of deleterious mutations occurs in autotetraploids. However, the variation of inbreeding depression with selfing depends on the dominance coefficients associated with the three heterozygous genotypes. Inbreeding depression can either increase or decrease with the selfing rate, and does not always vary monotonically. On the basis of this results, expected issues for the evolution of the selfing rate are discussed.