Diversity assessment of seedlings from self-pollinated Sangiovese grapevines by ampelography and microsatellite DNA analysis

A population of Vitis vinifera L, seedlings deriving from a single self-pol linated Sangiovese vine were assayed for diversity by ampelographic and gen etic techniques. After field-transplantation in 1987, the seedlings were in itially screened in 1995. Twenty-four seedlings were of standard Vigour and grape production. Woody cuttings from the 24 seedlings and the mother plan t were self-rooted in 1995, and each Vine was morphologically analysed and compared in 1997 using 31 descriptors of the ampelographic data sheet (OIV 1983) which are also recommended by UPOV for varietal identification - thre e for young shoots, 7 for shoots at bloom, 17 for adult leaves, one for flo wers and 3 for berries. - In 1996 DNA was extracted from young apical leave s of the mother plant and the 24 seedlings. Ten molecular microsatellites, VVS1, VVS2, VVS5, VVS16, VVS29, VVMD5, VVMD6, VVMD7, VVMD17 and VVMD28, wer e used for progeny and mother plant comparison. The descriptor-based analys is showed that 12 of the 24 seedlings were morphologically similar amongst themselves and not different fr-om the mother; the remaining 12 differing f rom each other and from the parent. The microsatellite analysis differentia ted all 24 seedlings from the mother plant. Only two seedlings showed the s ame allele patterns at the 10 tested loci, although they differed morpholog ically. The results of both analyses indicate that self-pollination can gen erate phenotypically similar individuals that are difficult to distinguish morphologically, while their genetic polymorphism can easily be detected by microsatellite analysis. Thus it is possible, as suggested by RIVES (1961) , that certain ancient cultivars comprise a number of clones that derive vi a vegetative propagation from closely related mother plants. Corroboration of the polyclonal origin in such cases can be performed by techniques combi ning morphological and molecular approaches.