Abstract:

In potato breeding，it is difficult to improve the traits of interest at the tetraploid level due
to the tetrasomic inheritance. A promising supplement is diploid breeding due to the simple genome. Thus，
it is necessary to assess the genetic diversity of diploid potato germplasm for efficient exploration and
deployment of desirable traits. In this study，we used simple sequence repeat（SSR） markers to evaluate
the genetic diversity of diploid potato cultivars，which can provide a molecular basis for diploid potato
breeding. To screen polymorphic SSR markers，55 pairs of SSR primers were employed to amplify 39
cultivars with relatively distant genetic relationships. Among them，12 SSR markers with high
polymorphism located at 12 chromosomes were chosen to evaluate the genetic diversity of 192 diploid potato cultivars. The primers produced 6 to 18 bands with an average of 8.2 bands per primer. In total，98
bands were amplified from 192 cultivars，97 of which were polymorphic. Cluster analysis using UPGMA
showed the genetic relationships of all accessions tested：One-hundred and eighty-six of the 192 accessions
could be distinguished by only 12 pairs of SSR primers，the 192 diploid cultivars were divided into 11
groups，and 83.3% constituted the first group.

Key words: Solanum tuberosum, diploid potato cultivated species, SSR marker, genetic diversity, DNA fingerprinting