Genetic Relationships among Slovenian Pears Assessed by Molecular Markers

Abstract

A sample of 94 pear (Pyrus L.) genotypes, traditionally present in the Slovenian landscape, was analyzed by amplified fragment length polymorphism (AFLP) and SSR (SSR), focusing on the assessment of genetic relationships. The analyzed samples involved germplasm of Pyrus communis L., P. nivalis Jacq., and P. pyraster L. The AFLP technique, using five EcoRI and MseI primer combinations, revealed molecular polymorphism at a level of 65.95%, representing 93 polymorphic bands among the total of 141 scored. With SSR analysis, 64 polymorphic alleles were found at seven microsatellite loci, with an average of 9.14 alleles per locus. Genetic distances among the individuals being studied were calculated using the Dice coefficient of similarity, and a dendrogram supported by AFLP and SSR data was constructed using the neighbor-joining method. The clustering method grouped the analyzed genotypes into three main clusters. The first cluster included the P. communis germplasm. The genotypes resembling P. nivalis were grouped in the second largest cluster, which could be divided in to four subclusters. The germplasm of P. pyraster, in this cluster, was found to be much less distinct than we had assumed. The most typical cultivar group in the third cluster was ‘Vinska Mostnica’. The study indicated that P. nivalis germplasm is frequently present in Slovenia, but not as a pure species.