|ZAKI, HAITHAM - Minia University|
|CHRISTENSEN, CHRISTIAN - University Of Florida|
|ZOTARELLI, LINCOLN - University Of Florida|
Submitted to: American Journal of Potato Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/1/2017
Publication Date: 8/28/2017
Publication URL: http://handle.nal.usda.gov/10113/5886689
Citation: Haynes, K.G., Zaki, H.E., Christensen, C., Ogden, E.L., Rowland, L.J., Kramer, M.H., Zotarelli, L. 2017. High levels of heterozygosity found for 15 SSR loci in Solanum chacoense. American Journal of Potato Research. https://doi.org/10.1007/s12230-017-9602-4.
Interpretive Summary: Genetic variation is a necessary prerequisite for improving domesticated plants through breeding; without it, breeding progress would be impossible. Genetic variation can be readily ascertained using DNA markers. Solanum chacoense is a wild potato species that has resistance to disease and insect pests. The species is also salt tolerant and readily takes up nitrogen for plant growth. In order to determine how best to utilize this wild species in potato breeding, we first evaluated genetic variation using DNA markers. The greatest genetic variation occurred among accessions rather than between plants within accessions. As a result, breeders looking for variation in this wild species can reduce the number of plants that must be evaluated within an accession and instead utilize their resources to evaluate a greater number of different accessions. This research will benefit potato breeders using this wild species to improve traits in cultivated potatoes.
Technical Abstract: Genetic variation is a necessary prerequisite for improving domesticated plants through breeding; without it, breeding progress would be impossible. Genetic variation can be readily ascertained with co-dominant DNA markers, such as simple sequence repeats (SSRs). Twenty-four SSR markers specifically designed for potatoes were evaluated to determine the extent of genetic variation within and among ten accessions of Solanum chacoense (chc), a wild potato species with potential traits for salinity tolerance and high nitrogen uptake efficiency. Fifteen of these markers were informative: there was no polymorphism in one of the markers, four of the markers showed evidence that more than one locus was being amplified, and the other four markers failed to consistently amplify products. The number of alleles amplified among these 15 markers ranged from two to eleven with an average of five. Based on allele frequencies, observed heterozygosity was significantly less than expected heterozygosity for 14 of the markers. In a variance decomposition, variation among accessions was the largest proportion of variance for three markers, variation within genotypes within accessions (clone-to-clone) was the largest proportion for three markers, and for the other nine markers variation within genotypes was the largest proportion. These results suggest that genetic variation in chc can be maximized using a breeding strategy that maximizes the number of accessions.