Genetic diversity of pear germplasm in Bosnia and Herzegovina, as revealed by SSR markers

Abstract

Bosnia and Herzegovina (BIH) pear germplasm in the ex situ field collection at the University of Banja Luka was characterised with simple sequence repeat (SSR) markers in order to reveal redundancies, determine genetic diversity and confirm uniqueness. European pear (Pyrus communis L.) 67 accessions of the BIH collection and 7 reference cultivars of the ex situ collection at SLU in Balsgard, Sweden were analysed using a set of 10 SSR markers. All markers resulted in good amplification and easy scoring of marker alleles One-third of accessions appeared to be triploid. A total of 112 alleles were amplified in unique diploid genotypes with on average 11.2 alleles per marker. Mean observed heterozygosity (Ho) was 0.72, mean expected heterozygosity (He) – 0.80 and mean Shannon index (I) – 1.96. Inbreeding coefficient (FIT ) for diploid accessions ranged from −0.06 to 0.28 (mean 0.02) and Wright’s inbreeding coefficient (FIS ) – from −0.27 to 0.17 (mean −0.03). In the BIH pear collection, mean value of genetic differentiation (FST ) between the reference cultivars and pear accessions was 0.05. Principal coordinate analysis (PCoA) divided the 74 pear accessions into three groups. The first group consisted of diploid, reference and possible triploid pear accessions, while the second and third groups contained only BIH possible triploid accessions. Overall, the results revealed high levels of polymorphism and uniqueness, indicating that BIH pear germplasm represents very diverse and valuable material for future breeding programmes.