Isozymes and canonical discriminant analysis to identify pistachio (Pistacia vera L.) germplasm

Canonical discriminant analysis (CDA) of morphometric data of buds, leaves, and fruit, as well as isozyme analysis (esterase, peroxydase, and acid phosphatase) of leaf samples, were used to identify eight male pistachio selections and 10 female pistachio cultivars. According to the CDA, 77% and 93% of the total variance was summarized by the first three canonical discriminant functions for the female and male selections, respectively. Fruit characteristics, particularly fruit fresh and dry weights and fruit length, accounted for most of the discriminatory power for the female cultivars, while the dimensions of the leaves, principally leaf rachis length, were the most effective discriminating character for the males. Isozyme analysis showed a higher degree of polymorphism in the male than the female genetic pool. Hence, using only three enzymes, it was possible to identify all the male selections, but only 50% of the female. Peroxidase polymorphism clearly demonstrated the greater phylogenetic distance between ‘Kerman’ and the local cultivars, as well between ‘Cerasola’, a quite different cultivar with a reddish hull, and the others tested. The combination of CDA and isozyme analysis enhanced the possibility of uniquely identifying the female cultivars.