Genetic and phenotypic diversity in Pistachio (P. vera L.) germplasm collected in Mediterranean countries

Within a cooperative research programme on the conservation and utilization of P. vera L. genetic resources coordinated by the International Plant Genetic Resource Institute (IPGRI), special priority was given to the identification of germplasm and the evaluation of genetic diversity. To satisfy the objectives of this project, 49 male and 44 female accessions originating in Mediterranean and Central Asian countries, and collected in Italy, Greece, Morocco, Spain and Turkey, were examined for a common set of qualitative and quantitative morphological descriptors previously confirmed to be highly discriminatory. The phenotypic data recorded were assessed using cluster analysis. Fingerprinting analysis was conducted using random amplified polymorphic DNAs (RAPDs) extracted from the leaves of 24 accessions (8 male and 16 female cultivars) gathered in a collection located in Sicily. The results from these molecular marker analyses were used to produce matrices of dissimilarity and to perform cluster analysis. On the whole, a high degree of polymorphism was detected both on the phenotypic and genetic traits examined. Among the female accessions, cluster analyses both on morphological and biomolecular characters did not separate the Mediterranean from the Iranian-Caspian genotypes. The results obtained using DNA analysis together with those from the morphological descriptors increased the level of the accuracy for germplasm identification and improved the reliability of the studies on genetic/phenotypic diversity and relatedness among the tested accessions.