SSR polymorphism of modern cultivars and autochthonous forms of the pear tree from North Caucasus

Genetic similarity and relatedness within the set of pear genotypes including autochthonous Circassian cultivars from North Caucasus, European cultivars, accessions of Pyrus caucasica Fed., and modern Russian cultivars were estimated on the basis of analysis of SSR loci. The level of polymorphism for the studied loci varied from 11 to 15 alleles per locus in the set of 29 samples of pears. A higher level of allelic polymorphism of SSR loci was revealed for a set of P. caucasica samples in comparison with modern cultivated cultivars: from 9 to 12 alleles for P. caucasica and from 6 to 8 alleles for modern cultivars. Specific alleles for the mentioned groups of pears were identified. UPGMA clustering revealed two distinct groups: one includes P. caucasica accessions and autochthonous Caucasian cultivars and the other group includes all cultivated European and Russian pear cultivar. The results support the hypothesis of an isolated gene pool formation of autochthonous pear cultivars of the North Caucasus and their probable origin from the wild P. caucasica .