Evaluation of
Stratified Sampling Strategies to Access Maximal Genetic Diversity from Crop
Plant Genebank Collections Syverson, R.L. and J.M.
Bradeen
American Phytopathological Society North Central Region Annual
Meeting (
Wild germplasm is a frequently accessed source of genes for crop improvement. For potato, the wild species Solanum bulbocastanum is a source of late blight and Verticillium resistance. We seek a plant germplasm sampling strategy to maximize genetic diversity with minimal resource input. We used AFLP estimates of genome diversity to evaluate stratified sampling methodologies based on subspecies affiliations, geographic origin, and intra- vs. inter-population relationships for more than 200 S. bulbocastanum genotypes from the USDA Potato Genebank. Included were 2-5 S. bulbocastanum genotypes from each of 42 populations representing 3 morphologically defined subspecies and the entire geographic range of the species. Genotypes were analyzed with 1-3 AFLP primer pairs. Dendrograms do not support defined subspecies. Genetic distance between genotypes correlates poorly with geographic distance between populations. Considerable genetic variation occurs both within and between populations. Our results will be interpreted relative to sampling strategies for crop plant germplasm utilization.