Computer simulation was undertaken to compare the genetic consequences of asexual (somatic doubling) and sexual (2n gametes) polyploidization. The coefficient of inbreeding at a locus, the number and frequency of genotypes at a locus, and the proportion of tri- and tetra-allelic genotypes were considered. The factors considered to estimate the genetic consequences were (i) mechanisms of sexual polyploidization, by first division restitution (FDR) × second division restitution (SDR), FDR × FDR, or SDR × SDR; (ii) position of the locus in relation to the centromere, which affects the gametic output in 2n gamete formation and thus the probability of single-exchange tetrads in meiosis during 2n gamete formation (p value); and (iii) allelic diversity at a locus. In comparing asexual and sexual polyploidization, regardless of the position of a locus in relation to the centromere, sexual polyploidization generally indicated less inbreeding, more genotypic diversity, and a higher proportion of tri- and tetra-allelic genotypes. When allelic diversity at a locus was increased, these characteristics were even more prominent. When only two alleles are possible at a locus, somatic doubling would not be inferior to sexual polyploidization. Overall results favored SDR × FDR and FDR × FDR as a mode and mechanisms of polyploidization. The genetic variations produced by 2n gametes could be attributed to "combining ability of 2n gametes."Key words: asexual polyploidization, sexual polyploidization, inbreeding, heterozygosity, combining ability of 2n gametes.
Nature of 2n Gamete Formation and Mode of Inheritance in Interspecific Hybrids of Diploid Vaccinium darrowii and Tetraploid V. corymbosum