Outcrossing rates as related to plant density in phlox drummondii

Abstract

Outcrossing rates were investigated in 20 populations of Phlox drummondii using polymorphic allozyme loci. The analysis of progeny genotype arrays gave outcrossing estimates which varied from t = 0·69 to 1·01; the mean was 0·86 The estimated outcrossing rate deviated significantly from random mating in 13 populations. The deviation was due principally to crossing among relatives. Outcrossing rates were a weak inverse function of density. At one site the density of some subpopulations was artifically reduced; and the outcrossing rates in these subpopulations were significantly greater than in adjacent unmanipulated subpopulations. © 1990 The Genetical Society of Great Britain.