Use of RAPD markers to assess genetic diversity in two model species at the US-Potato Genebank

Research in conservation strategies is important for future decisions at the US-Potato Genebank. Thus, Random Amplified Polymorphic DNA (RAPD) markers were used to assess genetic relationships among two model potato populations: Solanum jamesii (2n = 2x = 24) and S. fendleri (2n = 4x = 48). The objectives were to determine (1) effects of seed increase on germplasm integrity, (2) whether in situ populations still are representative of ex situ populations, (3) worth of conservation of poorly documented populations and (4) association of genetic variation and eco-geographic structure to target areas for explorations.; Genetic relationships between increase generations within accessions revealed that comparisons between populations were not significantly different. Only one S. jamesii accession showed significant change in gene frequencies. Findings suggest that minimal change of genetic diversity occurred using genebank techniques standard at NRSP-6.; RAPDs measured differentiation between potato germplasm maintained in the US genebank and current in situ populations recollected from original native sites. Results showed significant differentiation between genebank-conserved and recollected populations for all 7 comparisons of S. jamesii and 12 of 16 within S. fendleri. This result may have an important impact on future genebank decisions on value of re-collections and in situ preservation.; RAPDs characterized a “mystery” population of Solanum sucrense (2n = 4x = 48), for which documentation was lacking. Similarities between this population and each one of 30 other S. sucrense populations revealed that all populations within this species and the mystery population, are significantly different from being duplicates, and are therefore worthy of separate conservation. RAPDs also distinguished the mystery population from closely related species S. oplocense, S. gourlayi and S. tuberosum ssp. andigena suggesting that it is also not a duplicate of a population of these species.; Ninety-six potato populations collected from the United States were used to determine associations between genetic variation and eco-geographical structure. Results suggest that patterns of differentiation are not explained by differences in eco-geographical structure. Remarkably, geographical separation, a parameter considered important when collecting germplasm, also did not predict genetic differentiation. Eco-geographical variables significantly predicted genetic diversity in S. fendleri. Such information could help to enhance efficiency in collecting strategies.