Collection and Evaluation of Genetic Diversity and Population Structure of Potato Landraces and Varieties in China

Abstract

China is the world's leading country for potato production but potato is not native to China. To gain insights into the genetic diversity of potato germplasm various studies have been performed but no study has been reported for potato landraces in China. To improve the available genepool for future potato breeding programs, a diverse population containing 292 genotypes (including foreign elite lines, local landraces and cultivars) was developed and genotyped using 30 SSR markers covering the entire potato genome. A total of 174 alleles were detected with an average of 5.5 alleles per locus. The model-based structure analysis discriminated the population into two main sub-groups, which can be further subdivided into seven groups based on collection sites. One sub-group (P1) revealed less genetic diversity than other (P2) and contained a higher number of commercial cultivars possibly indicating a slight reduction in diversity due to selection in breeding programs. The P2 sub-group showed a wider range of genetic diversity with more new and unique alleles attained from wild relatives. The potato landraces, clustered in sub-population P1 may be derived from historical population imported from ancient European and International Potato Center genotypes while sub-population P2 may be derived from modern populations from International Potato Center and European genotypes. It is proposed that in the first step, the potato genotypes were introduced from Europe to China, domesticated as landraces, and then hybridized for modern cultivars.

Keywords: SSR; domestication; genetic diversity; landraces; population structure; potato.

FIGURE 1

Population Structure of 292 diverse genotypes, the graphical presentation of estimation of posterior probability (A) and ΔK (B), as well as tabulated values (D) and, Q-values based population structure (C) of 292 diverse potato genotypes with 1–10 K populations. The colored region grouped the genotypes in corresponding populations as Red (P1) and Green (P2).

FIGURE 2

Structural characterization of 292 diverse genotypes. (A) Phylogenetic tree of all 292 genotypes estimated by 174 alleles of 30 SSR markers, the clades 1 and 2 represent the sub-populations P1 and P2, respectively, while sub-population P1 subdivided by alphabets A–E and sub-population P2 subdivided by alphabets A–F. (B) The dendrogram for various groups in P1 and (C) in P2. (D) The region based frequency of genotypes in various groups of Sub-populations. Hence, Eu, European genotypes; LAN, Landraces in China; NC, Varieties from Northern China; SWC, Varieties from Southwest of China; YS, local cultivars.