Variabilità di biotipi di “Sangiovese” reperiti nella zona della DOC “Montecucco”

A population of “Sangiovese” and “Ciliegiolo” biotypes (“Ciliegiolo” is considered to have close parentage relation with “Sangioviose”) showing differences of some morphological traits (shoot tip colour; leaf size, shape and tomentosity) present in “Montecucco” DOC area have been analysed by DNA molecular markers. The polymorphism of 10 microsatellite loci, included the 6 microsatellite loci indicated in the EU-project GENRES CT96 No 81, (VVS2, VVMD5, VVMD6, VVMD7, VVMD17, VVMD21, VVMD24, VVMD27, ssrVrZag62 e ssrVrZag79) have been analysed. In addition have been analysed the REMAP polymorphism (REtrotransposon-Microsatellite Amplified Polymorphism) a technique showing the retrotransposons insertional polymorphism by the amplification of DNA fragment between a retrotransposon and a microsatellite locus. Two REMAP primer combinations have been chosen on the bases of previous results (D’Onofrio et al., personal communication): one combination for Tvv1 retrotrasposons and the other one for Gret1 retrotrasposons. The polymorphism of both type of molecular markers have been translated in presence/absence matrixes, the similarity analysis have been performed using the Nei coefficient for microsatellite and the simple matching similarity index for REMAP, and the relative dendrograms have been build using the UPGMA methods. Furthermore, the degree of genetic diversity displayed by both molecular marker systems have been evaluated by the Shannon’s index and the polymorphic information content (PIC). The molecular analysis not revealed genetic differences among the most part of accessions showing significant differences in morphological traits, while in some cases a genetic diversity have been detected among accessions characterised by some ampelographic trait convergences.