THE PRESENCE OF GENETIC VARIABILITY IN GRAPE VARIETIES

Аннотация

222 cultivated (Vitis vinifera) and 22 wild (V. vinifera ssp. sylvestris) grape accessions were analysed for genetic diversity and differentiation at eight microsatellite loci. A total of 94 alleles were detected, with extensive polymorphism among the accessions. Multivariate relationships among accessions revealed 16 genetic groups structured into three clusters, supporting the classical eco-geographic grouping of grape cultivars: occidentalis, pontica and orientalis. KEYWORDS: Genetic, grape, cultivate, wild, allel, occidentalis, pontica, orientalis. INTRODUCTION originally classified as V. sylvestris C.C. Gmelin occurring from north-eastern Afghanistan to Cultivated grape, Vitis vinifera L., is the sole the southern borders of the Black Sea and the European representative of the genus Vitis L., Caspian Sea. However, based on a recent a large member of Vitaceae with y60 species. archaeological finding in the Zagros Two-thirds of these species are native to mountains of Iran, McGovern et al. suggested North America and onethird is distributed 5400–5000 BC as the probable period of over central and east Asia. The cultivated domestication of the grape. Currently, most grape is believed to have been domesticated botanists regard the wild ancestral grape V. around 4000 BC from a perennial wild grape “THE PRESENCE OF GENETIC VARIABILITY IN GRAPE VARIETIES” P age 29 | 5 sylvestris as the primitive form of the synonyms, a problem that plagues germplasm cultivated grape because of the close collections. Traditional methods of describing morphological resemblance and free gene grape vine varieties based on the plant’s flow between them (Heywood & Zohary, vegetative and reproductive traits 1991) and consequently have reduced its (ampleography) have contributed greatly to taxonomic status to subspecies level within establishing the identity and relationships the V. vinifera crop complex. The wild grapes among V. vinifera cultivars. Nevertheless, are predominantly forest climbers and occur ampelographic traits are often plastic, with a in disjunct populations from the Atlantic coast large genotype–environment interaction to Tadzhikistan and the western Himalayas. component rendering them less useful in They occasionally come into contact with classifying closely related cultivars. Early cultivated forms in nearby vineyards, forming efforts to classify the eco-geographic complex introgressive hybrid swarms in variation within the cultivated grape resulted transition zones. Domestication of grape in the classification of cultivars into groups: involved a shift in the mode of reproduction occidentalis, the small-berried wine grapes of from dioecious to hermaphroditic, ensuring western Europe; orientalis, the large-berried self-pollination without the need for external table grapes of West Asia; and pontica, the pollen donors. The earliest signs of grape intermediate type from the basin of the Black cultivation come from Chalcolithic and Early Sea and eastern Europe. Levadoux Bronze Age (3500–2300 BC) sites in the summarized the eco-geographic Jordan Valley, where wild and cultivated differentiation of wild and cultivated V. grapes provided fresh fruits, easily stored vinifera populations from western Europe and raisins and juice for fresh consumption and the Mediterranean region, and discussed the fermentation into wine. Over the next 2000 consequences of isolation of eastern and years, grape cultivation spread to the eastern, western populations during the glacial period northern and western parts of Eurasia and to and post-glacial proliferation for population northern Africa, following the trade routes differentiation, climatic adaptations and early and migration of ancient tribes. Traditional selection and cultivation by man. More viticulture was based on thousands of distinct recently, Bisson proposed the eco-regional cultivars exhibiting a wide range of classification for French cultivars and adaptations, growth habits and fruit discussed the implications for grape breeding. characteristics. Currently, over 6000 cultivars A wide range of biochemical and molecular are documented, including wine, table and markers are being used to characterize and raisin types. Nevertheless, cultivar names are classify grape germplasm collections. often ambiguous owing to transliteration, the However, the use of molecular markers to substitution of local or regional names for the study genetic structure and differentiation in original cultivar names, the presence of V. vinifera is limited to a few investigations. variants within cultivars (clones) and poor Microsatellite markers, being abundant, documentation of passport data, which multiallelic and highly polymorphic, provide includes ecogeographical, climatological and an efficient and accurate means of detecting ethnographic information associated with genetic polymorphism. Most importantly, germplasm accessions. Moreover, the wide their co-dominant nature makes them the distribut