ISHS Acta Horticulturae 528: VII International Symposium on Grapevine Genetics and Breeding
WITHIN CULTIVAR GRAPEVINE VARIABILITY STUDIED BY MORPHOMETRICAL AND MOLECULAR MARKER BASED TECHNIQUES |
| Authors: | R. Botta, A. Schneider, A. Akkak, N.S. Scott, M.R. Thomas |
| Keywords: | Vitis vinifera, ampelography, DNA, microsatellite, SSR |
| Abstract:
Fifteen clones of the grapevine cultivar Nebbiolo, chosen as belonging to five biotypes (Lampia, Bolla, Rose3, Michet and Chiavennasca) according to the traditional classification of this cultivar in its growing area in northwest Italy, were examined for morphologic and biometric characters and for DNA profiles using microsatellite markers. The aim of the research was to investigate the phenotypic variability already observed for 'Nebbiolo' and to verify the existence of genetic diversity within the cultivar. Morphologic observations were carried out using the OIV descriptors for shoot, leaf and fruit. Leaf samples were examined by biometric techniques. For the DNA typing five microsatellite loci were analysed by an Applied Biosystem 373A DNA sequencing apparatus using GENESCAN software and by electrophoresis on sequencing gel, followed by chemiluminescence detection. The morphologic and biometric differences revealed the existence of three groups of clones. The first group includes three biotypes: Lampia and Bolla, grown in the area of Alba (Piedmont) where Barolo and Barbaresco wines are produced, and Chiavennasca, from Valtellina in Lombardy. The biotypes Rosè and Michet (both from Alba) were distinct from the other 'Nebbiolo' biotypes and from each other. The morphologial differences found in the Michet clones are mainly due to the presence of the grapevine fanleaf virus. DNA analysis showed that the biotype Rosè is genetically distinct from the others, although closely related to them. DNA typing distinguished 2 profiles, one for the Rosè, and a second shared by all the other genotypes. The results indicate that at least two causes of phenotypical polymorphism should be considered for explaining the variability observed in grapevine cultivars of ancient origin: vine phytosanitary conditions and genetic diversity. | |
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