Diversity in Free-living Populations of Cucurbita pepo (Cucurbitaceae) as Assessed by Random Amplified Polymorphic DNA

Abstract

Abstract One area of risk assessment for transgenic crops concerns cross-compatible wild and weedy relatives. In squash (Cucurbita pepo), free-living populations are diverse in their distributions, ecologies, histories, and genetic and phenotypic compositions. As part of the effort to understand this diversity, random amplified polymorphic DNA (RAPD) data were collected from 37 wild or weedy populations and 16 cultivars, which together represented all infraspecific taxa of C. pepo. Twenty-six primers yielded 70 scorable and variable markers. The presence/absence of bands for these markers produced a data matrix which was analyzed using cluster analysis. The analysis confirmed the relationships among infraspecific taxa that had been revealed, in part, in previous genetic analyses (e.g., isozymes, chloroplast DNA restriction-site mutations, inter simple sequence repeats). Also supported were findings of varying degrees of gene flow from cultivars into free-living populations. Some of the RAPD variation in s...