SELF-INCOMPATIBILITY IN IPOMOEA-PES-CAPRAE (CONVOLVULACEAE)

The breeding system of Ipomoea pes-caprae, the goat's foot or beach morning glory, was examined in two populations bordering the Gulf of Mexico in order to investigate the self-incompatibility mechanism of the species, especially the number of s alleles in two populations. Ipomoea pes-caprae possesses a sporophytic multi-allelic incompatibility system which is rare in flowering plants. The maximum likelihood estimates of the number of s alleles in the samples of plants from Grand Isle, Louisiana, and Progreso, Yucatan, are four and seven, respectively. Although self-incompatibility appears to be an incongruous feature of a pantropical colonizing species, long-range dispersal of pollen and water-dispersed seeds enhance the self-incompatibility system to promote genetic diversity and a widespread distribution.