Origin and genetic diversity of Tunisian grapes as revealed by microsatellite markers

• Published in: Scientia horticulturae 2009, Vol.120 (4), p.479-486
• Main Authors: Zoghlami, N., Riahi, L., Laucou, V., Lacombe, T., Mliki, A., Ghorbel, A., This, P.
• Format: Article
• Language: English
• Subjects: Agricultural sciences; Agronomy. Soil science and plant productions; alleles; Biological and medical sciences; cultivar identification; cultivars; DNA fingerprinting; Fundamental and applied biological sciences. Psychology; Generalities. Genetics. Plant material; Genetic diversity; genetic markers; Genetic resources, diversity; genetic variation; Genetics and breeding of economic plants; genotype; grapes; heterozygosity; Homonymy; Horticulture; landraces; Life Sciences; loci; microsatellite repeats; molecular sequence data; Parentage; Plant material; SSRs; Tunisian grapes; UPGMA clustering; Vitis vinifera
• ISSN: 0304-4238; 1879-1018
• DOI: 10.1016/j.scienta.2008.12.011

Ten SSR loci, previously developed for grapevine, were analyzed to evaluate the genetic variability, cultivar relatedness, and parentage in a collection of 61 autochthonous Vitis vinifera cultivars from Tunisia. The number of alleles per locus ranged from 6 to 11, while the number of genotype patterns varied between 10 and 21. The expected heterozygosity varied between 0.621 and 0.855 and the observed heterozygosity was higher than 0.9 at 4 loci (VVMD28, VVMD5, VVIP31 and VVS2) indicating that the SSRs were highly informative. Cluster analysis using unweighted pair group method with arithmetic averaging (UPGMA) suggested 14 groups among studied cultivars and 53 grapevine denominations out of 61 were unequivocally distinguished, with all accessions showing at least one-specific combination of alleles. On the other hand, in order to overcome the existing confusion in Tunisian grapevine nomenclature, of the analyzed homonymous pairs of cultivars, only ‘Balta 2’ and ‘Balta 3’ have shown identical allelic profiles, consistent with their being the same genotype. Hence, nomenclature distinction is meaningless and only one denomination should be retained. Due to the high overall power of exclusion ( Q) (greater than 99.99%) and to the absence of null alleles, the set of microsatellite loci used is appropriate to determine parentage in Tunisian grapevines beyond any reasonable doubt. The analysis of fingerprints indicated that the Tunisian grape vines have evolved through out crossing between five possible parents: Balta 1, Beldi Baddar, Beldi Rafraf, Beldi Local Rafraf and Khedhiri 3.