The mating system and genetic structure in a perennial grass, cynosurus cristatus l

Abstract

The breeding system, genotypic structure, and degree of spatial genetic differentiation were investigated in a population of the perennial grass Cynosurus cristatus using four polymorphic allozyme loci. Both incompatability studies and analysis of progeny genotype arrays gave outcrossing rate estimates of t =0·98, not significantly different from random mating. Levels of inbreeding and of gametic disequilibrium between allozyme loci were negligible. Genetic differentiation among adult subpopulations was very low (GST = 1·14 per cent). Among pollen pool subpopulations genetic differentiation was even lower (GST =0·28 per cent). It is concluded that substantial pollen flow prevents the development of significant genetic differentiation through random genetic drift in different areas of the same population. © 1985 The Genetical Society of Great Britain.