THE INFLUENCE OF FLOWER COLOR ON OUTCROSSING RATE AND MALE REPRODUCTIVE SUCCESS IN IPOMOEA PURPUREA.

Experimental populations of the annual plant, Ipomoea purpurea, composed of individuals belonging to two flower color morphs were studied to determine the effect of flower color on outcrossing rate and reproductive success as a male parent. Analyses of parent and offspring genotypes show that the pigmented and white morphs outcross at similar rates, but that the white morph is favored as a pollen donor. The result suggests that the dynamics of selection occurring at the locus coding for white versus pigmented flowers are more complex than previously believed. Factors such as frequency-dependent outcrossing rates and epistatic effects of the white allele may be operating. The results also suggest that pollinator observations are unreliable indicators of the actual mating system. © 1985 The Society for the Study of Evolution.