ARS | Publication request: LEVELS OF INTRA-SPECIFIC AFLP DIVERSITY IN TUBER BEARING POTATO SPECIES WITH DIFFERENT BREEDING SYSTEMS AND PLOIDY LEVELS

Submitted to: Solanaceae International Congress Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: May 29, 2006
Publication Date: July 30, 2006
Citation: Bryan, G., Mclean, K., Ramsay, G., Waugh, R., Spooner, D.M. 2006. Levels of intra-specific aflp diversity in tuber bearing potato species with different breeding systems and ploidy levels [abstract]. Solanaceae International Congress Proceedings. p. 218.

Technical Abstract: We have employed Amplified Fragment Length Polymorphism (AFLP) analysis to examine levels of intra-specific polymorphism in wild and cultivated potato taxa differing in geographic origin, ploidy and breeding system. We have generated 449 polymorphic AFLP fragments for 619 plants, representing 17 genebank accessions of 15 potato taxa as well as a "pseudo-population" comprising a single individual from each available accession of each taxon. Diversity measurements and average genetic similarities were compared between each accession and the relevant taxon-wide measure of diversity. Our data confirm the expected tendency of considerably lower amounts of genetic diversity within accessions of inbreeders than outbreeders. Levels of diversity among single individuals drawn from different accessions of the same taxon are of similar magnitude in inbreeders and outbreeders. Ratios of between to within population diversity vary from less than 2-fold for outbreeders such as the cultivated tetraploid species S. tuberosum ssp. tuberosum to approximately 40-fold for the inbreeding wild hexaploid S. demissum. We have also found that an individual plant of an inbreeding species contains much more of the total marker complement of its parent population than an outbreeding plant. Similar patterns are observed on comparison of average within-accession genetic similarity values, with plants of inbreeding taxa being of greater average similarity than outbreeders. Overall, these data suggest that a single plant is highly representative of an inbreeding or moderately outbred accession for diversity and phylogenetic studies. However, for highly heterozygous outbreeders a deeper sampling of more individuals is recommended, especially for studies where resolution of closely related populations is required. It is hoped that simulation studies will help to further resolve this question.