Abstract:

Genotypes of six natural populations of Sorbus pohuashanensis were studied using horizontal starch gel electrophoresis and the mating system was analysed at eight loci(Pgm-1, Pgm-2, Pgm-3, Pgi-1, Pgi-2, Pgd-1, Pgd-2, Pgd-3) using MLT software. Results indicated that the gametes ratio of each locus in pollen and ovule pools was mainly in balance in the six populations. The multi-locus outcrossing rates were above 0.981. The margin of multi-locus minus single-locus outcrossing rate(t_m-t_s) showed that slight inbreeding existed in the populations. Therefore, the mating system of S. pohuashanensis in the 6 populations is predominantly outcrossing. The inferred inbreeding depression(δ=1) from the electrophoresis data indicated severe inbreeding depression in the natural populations of the species.

Key words: Sorbus pohuashanensis, isozyme marker, outcrossing rate, inbreeding depression