GENETIC STUDIES IN A TROPICAL PINE - <em>PINUS</em> <em>KESIYA</em> III. THE MATING SYSTEM IN FOUR POPULATIONS FROM NORTHERN THAILAND

Abstract

Single and multilocus estimates of outcrossing rates in four populations of Pinus kesiya from northern Thailand were obtained using isozyme data. Multilocus estimates ranged from 0.68 to 0.97, which are comparable with estimates for other coniferous species. Comparisons of expected and observed inbreeding coefficients indicated excesses of heterozygotes over the frequencies expected from random mating in two populations. Evidence for spatial heterogeneity in allele frequencies was strongest in the same two populations, suggesting the possibility of matings occurring among trees in genetically distinct groups. In one population (Samoeng) there was an excess of homozygotes, compared with the equilibrium frequency expected from the estimated outcrossing rate.