Diversity in natural populations of wild Brassica oleracea as estimated by isozyme and RAPD analysis

Abstract

Naturally occurring populations of wild Brassica oleracea were collected in Spain, France, and Great Britain. Allele frequencies at four isozyme loci were determined for 18 populations, while five populations were screened using five random primers to generate RAPDs. Levels of homozygosity and gene diversity, H, were computed for each population using isozyme data and RAPD data when applicable. Homozygosity levels tended to be higher in smaller populations, which could also be observed as increased numbers of homozygous loci in smaller populations. Gene diversity values based on isozymes indicated considerable within population variation regardless of population size. The RAPID based gene diversities were significantly higher and the two exceptional populations displayed diversity levels more in keeping with the rest. The coefficient of gene differentiation, GsT, for populations in each region showed that the Spanish populations were more homogeneous than the French or British. When the GsT" for all populations was calculated using isozymes vs. RAPD data, the RAPD data gave a significantly lower value, a plausible result of the higher within population variation detected using RAPDs. Genetic distances between populations from different regions were also calculated from both data sets and used to produce phenograms. Clustering according to geographic region was not evident using either isozyme or RAPD data.

AFLP analysis of genetic diversity in leafy kale (Brassica oleracea L. convar. acephala (DC.) Alef.) landraces, cultivars and wild populations in Europe

“…This is to be expected for an outcrossing species, and is consistent with other studies done on outcrossing crop species (see e.g., Sanchez et al 2000;Andersen et al 2009). Among wild B. oleracea populations in France, England and Spain a similar value of populationdifferentiation (G ST = 0.37, based on isozyme data) was found (Lannér-Herrera et al 1996), whereas a somewhat lower value (F ST = 0.23, based on AFLP data) was found among wild populations in Britain (Watson-Jones et al 2006).…”

“…Not much is known about the levels of diversity found in kale landraces, but the diversity and structure of wild populations in England, France and Spain, have previously been investigated (Lannér-Herrera et al 1996;Raybould et al 1999;Watson-Jones et al 2006). With this study we estimate the baseline of diversity in kale landraces and their genetic structure.…”

An exploration of wild Brassica oleracea L. germplasm in Northern Spain

“…Other populations such as those of Onton (n. 33) and Barrika (n. 34) were also originally considered as small but have been shown to extend to both sides of the gulf and appeared two or three times larger when explored from the sea. In comparison with other areas in France and the UK, Spanish populations tend to be relatively smaller (Lann e er- Herrera et al 1996).…”

Genetic Diversity of Peanut (Arachis hypogea L.) Cultivars as Revealed by RAPD Markers

“…In recent studies, fingerprints based on different markers were compared using genotypes from different species. There were both agreements and disagreements in findings based on different markers and species: The study of Brassica oleracea by Lanner-Herrera et al (1996) [11], a moderate spearman's rank correlation (r = 0.38) between RAPD and isozyme distances was found. Russell et al (1997) [12] compared the levels of genetic variation among barley accessions revealed by RFLP, AFLP, SSR, and RAPD, and reported that when the spearman's rank correlation was used, the correlation between SSR and RAPD was 0.235, the highest correlation was found between RFLP and AFLP (0.708).…”