|Del rio, Alfonso|
Submitted to: American Journal of Potato Research
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/9/2009
Publication Date: 9/29/2009
Citation: Bamberg, J.B., Del Rio, A.H., Moreyra-P, R. 2009. Genetic Consequences of Tuber Versus Seed Sampling in Two Wild Potato Species Indigenous to the USA. American Journal of Potato Research. 86(5):367-372. Interpretive Summary: Potato is the most important US vegetable, and one of the best hopes for feeding an increasingly hungry world. Breeders need to keep producing better varieties to meet changing needs of the industry and preferences of consumers. Breeders get raw materials from genebanks, so it is in the interest of US Agriculture for the US Potato Genebank at Sturgeon Bay, Wisconsin to collect genes by the most efficient means. Potato has many wild relatives that grow in natural habitats, from which they can be sampled by genebank personnel either as tubers or seeds. When we compared the DNA fingerprints of two model species that had been collected as both tubers and seeds, we found that the most genes were collected as tubers for one species, but as seeds for the other species. This work shows that recognizing the different reproductive strategies of species might be an important consideration for choosing the most efficient way to sample them from the wild. The more we understand such factors, the more genes will be captured in the genebank, and the more genes will be available for potato researchers to use to improve the potato crop.
Technical Abstract: Wild potatoes reproduce in the wild (in situ) clonally by tubers or sexually by seeds. This study used model populations to assess the genetic consequences of sampling in situ tubers or in situ seeds for two indigenous potato species of the USA, Solanum stoloniferum PI 564039 (sto) and Solanum jamesii PI 605371 (jam) with RAPD markers. While sto is an inbreeding disomic tetraploid, jam is a diploid outcrosser. More RAPD bands were collected in tubers than in seeds for sto, apparently because two genetic types of tubers were collected, with only one of these types represented in seeds. The opposite was found for jam, in which some RAPD markers were found only in seeds, perhaps because they had been introduced from outside the tuber collection area in pollen. It has generally been assumed that collecting in situ seeds will result in capture of more genetic diversity. However, these results demonstrate how the form in which the most genetic diversity is captured can vary, perhaps depending on the breeding system of the species.