MULTIPLE PATERNITY IN ASCLEPIAS-SYRIACA USING A PAIRED-FRUIT ANALYSIS

We investigated the extent of multiple paternity within and between fr uits of the common milkweed, Asclepias syriaca, at one site. Using iso zyme polymorphisms at four loci and the maximum likelihood methods of Williams and Evarts (1989), we found no statistical evidence for multi ple paternity within fruits. When pairs of fruits obtained from indivi dual ramets were analyzed in a similar manner, extensive multiple pate rnity was observed, indicating that fruits on the same ramet are sired by different paternal parents. This extensive multiple paternity betw een fruits provides considerable opportunity for maternal choice via s elective fruit abortion.