Differences Between Patterns of Gene :Flow Inferred from RFLPs and Isozymes in Sea Beet are Consistent across Loci

The distribution of allelic variation at genetic marker loci can be used to estimate parameters such as rates of gene flow and effective population size in populations of crop relatives. These data are useful when designing strategies for the most efficient collection of crop genetic resources. Estimates of gene flow among populations of sea beet (Beta vulgaris ssp. maritima) differed depending on whether the data were from isozymes or restriction fragment length polymorphisms (RFLPs). The difference was not due to the effect of one or a small subset of aberrant' loci within one of the sets of markers. The data suggest that, where practical, sampling strategies should be based on data from more than one type of genetic marker.