Floral-color polymorphism in Ipomoea purpurea: biased inheritance of the dark allele is not a general explanation for its maintenance

A previous investigation reported the existence in a single population of the morning glory (Ipomoea purpurea) of non-Mendelian inheritance at the W locus influencing flower color. In addition, it was shown that the magnitude of biased inheritance in that population was sufficient to maintain a floral-color polymorphism at that locus at frequencies approximating those observed in natural populations. The current investigation was undertaken to determine whether this biased inheritance was characteristic of other I. purpurea populations, and thus whether it provides a general explanation for maintenance of the polymorphism. The current study found no evidence for biased inheritance in two additional polymorphic populations examined. Non-Mendelian inheritance thus seems unlikely to constitute a general explanation for the maintenance of this floral-color polymorphism in l. purpurea.