Mating system analysis in a natural population of Acacia nilotica subspecies leiocarpa.

The mating-system was investigated in a natural population of the tetraploid taxon Acacia nilotica ssp. leiocarpa using open-pollinated seeds from 15 families. Six-day-old germinated seeds were used for starch-gel electrophoresis. Three enzyme systems (ADH, EST-1, and 6PGD) were scored. Isozyme banding patterns and segregation of isozyme variants within families suggest that the species is an autotetraploid displaying tetrasomic inheritance. Estimates of single-locus (ts=0.358) and multilocus (tm=0.384) population outcrossing rates were homogeneous, and indicate substantial selfing in the population. Heterogeneity of outcrossing estimates among loci and families were marked, suggesting departure from the assumptions of the mixed-mating model. Implications of the result for the utilization of germplasm in tree-improvement programmes are noted.