First Report of a set of Genetic Identities in Prunus Rootstocks by SSR Markers

Prunus rootstocks play an important role in modern horticulture and commercial orchards owing to their responsibility for a wide range of characters from compatibility with cultivars to adaptation to biotic and abiotic stresses. In this study, Thirty Prunus rootstock samples were tested by 25 microsatellite markers in order to identify the genetic identity and relationships among them.17 SSR markers were useful in the discrimination of the samples on the basis of their unique molecular identities. Samples with similar codes such as (HS-401/HS-402/HS-403), (HS811/HS507/HS737/GF677), (HS126/HS-202), (HS-802/HS602) and (HS522/HS003/HS302) were shown mislabeled trees. Based on partial repeated bisection (RB ) data, the samples were grouped into six clusters which the largest cluster contained nine genotypes (all APPL, APU2 and APPU3). The second largest cluster consisted of eight genotypes (all AM, all APL, APU1, APU3 and APH10). APH rootstocks were placed into clusters two, three and six as well as cluster one which included only APPU rootstocks. The highest amount of the average internal similarities (Isim ) (0.973) belonged to cluster six, whereas the minimum amount of Isim (0.924) belonged to cluster three. The minimum level of the average external similarities (Esim ) was related to groups one (0.664) and six (0.638) indicating the highest genetic distance from other groups. The genetic identities and relatedness generated in this study provide a standard for further breeding attempts and will be used as a reference the cultivation of these promising newly released genotypes.