STUDY OF GENETIC DIVERSITY IN PLUM GENOTYPES USING SRAP MARKERS

The hexaploid European plums (Prunus domestica L. and Prunus domestica subsp. insititia (L.) C.K.Schneid.) are main traditional fruit tree culture in Romania and represent an economically important fruit species with limited information on its genetic structure. Our objective was to fingerprint 33 cultivars using four Sequence-Related Amplified Polymorphism (SRAP) primer pairs to estimate the genetic relationships among local and international cultivars. The primer pairs amplified a total of 70 alleles ranging from 14 to 21 alleles per marker. A wide range of fragment length was detected among the accessions, from 65 to 2000 bp. The mean number of alleles per primer combination was 17.5, with the most alleles obtained with SRAP80 (21 alleles), range between 65-1800 bp and the fewest alleles (14) were obtained with SRAP95, range between 150-2000 bp. The neighbor-joining dendrogram, based on Rogers genetic distance, of the plum germplasm studied, consisted of two main clusters of different sizes: 23 entries were grouped into cluster 1 and the remaining 10 entries were grouped into cluster 2. It is interesting that cultivars representing plum species with 6x and 2x ploidy levels were clustered together. Another interesting aspect observed refers to plum genotypes clustered closely on the dendrogram according to their pedigree, such as 'Dani' (P14) - 'Tita' (P15), 'Roman' (P7) - 'Early Rivers' (P9), 'Zamfira' (P6) - 'Pescăruș' (P33). Accessions within the Romanian landrace/old autochthonous cultivars group were not clustered together. Regarding the PCA, the first two principal axes accounted for 12.91% (CP1) and 10.46% (CP2) of the total variation, respectively, together explaining 23.37% of the total variability. Our results showed that SRAP markers represent valuable tools for genetic diversity study on Prunus domestica. To our knowledge, this is the first study using SRAP markers for characterization of P. domestica germplasm. In the future, this molecular genetic information can be combined with phenological and biochemical data to identify genes, quantitative trait loci (QTL) and molecular markers that can be used to improve the plum crop breeding program.