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Title: Diversity relationships among wild potato collections from seven “Sky Island” mountain ranges in the Southwest USA

Author
item Bamberg, John
item DEL RIO, ALFONSO - University Of Wisconsin

Submitted to: American Journal of Potato Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/19/2011
Publication Date: 12/5/2011
Citation: Bamberg, J.B., Del Rio, A.H. 2011. Diversity relationships among wild potato collections from seven “Sky Island” mountain ranges in the Southwest USA. American Journal of Potato Research. 88(6):493-499.

Interpretive Summary: The US Potato Genebank is the federal facility responsible for acquiring, preserving and distributing stocks for US potato researchers and breeders. For a mechanic, having a toolbox with more tools that are better organized and characterized helps get the job done more efficiently. Similarly, efficiency in potato improvement is enhanced when the genebank can provide breeders with the maximum diversity of genetic tools. One aspect of this is investigating which sources of acquired stocks have the most genetic richness. A total of almost 100 samples of wild potato had been collected from seven mountain ranges in the southwest USA. We generated over 1,000 DNA markers on each of these, and determined how often markers appeared in just one mountain range. In this way, we showed that two of the mountain ranges were contributing most of the novel genes detected in the overall set. Now we know that these two mountain ranges would be good places for future collecting expeditions aimed at expanding the genebank toolbox. Similarly, these populations can now be prioritized for screening for traits and preservation based on the relative number of unique markers they have. These new insights supporting efficient breeding allow the genebank to better serve the potato industry and potato-eating public.

Technical Abstract: The authors collected samples of 97 populations of the wild potato S. stoloniferum (previously fendleri) in the following seven mountain ranges of the southwest USA over seven years, 2004-2010: Chiricahua (CHI), Huachuca (HUA), Rincon (RIN), Guadalupe (GUA), Pinaleno (PIN), Santa Catalina (CAT), and Santa Rita (RIT). These and previous samples were compared with AFLP markers to determine which ranges have the most genetic richness. A total of 2079 bands were polymorphic over all populations, and 1256 were polymorphic among ranges. Of these 1256 bands, 275 occurred in only one range (= unique). All mountain ranges had some unique bands, but not equally, as PIN, with 31%, and CHI with 22% together accounted for over 50% of the unique bands in the seven ranges. An examination of populations within ranges showed that one localized area was the source of over 50% of the unique bands from PIN. This study demonstrates that DNA markers can identify collecting locations like PIN and CHI with particular genetic richness, and thus having high priority for further sampling for the genebank. Similarly, these populations already present in the genebank could be prioritized for evaluation and preservation based on the relative number of unique bands they contribute from their range.