A multivariate approach for the ampelographic discrimination of grapevine (Vitis vinifera) cultivars: application to local Syrian genetic resources

Genet Resour Crop Evol (2017) 64:1841–1851 DOI 10.1007/s10722-017-0561-x SHORT COMMUNICATION A multivariate approach for the ampelographic discrimination of grapevine (Vitis vinifera) cultivars: application to local Syrian genetic resources S. Khalil . J. Tello . F. Hamed . A. Forneck Received: 29 May 2017 / Accepted: 29 August 2017 / Published online: 21 September 2017 Ó The Author(s) 2017. This article is an open access publication Abstract Due to its unique historical and geographical emplacement, grapes have been cultivated in the Syrian Arab Republic for more than 5000 years, so the characterization of its local genetic resources is paramount for understanding grapevine natural diversity. In this work, different local Syrian table grape cultivars were characterized for 42 traits related to plant phenology, shoot, leaf, cluster, berry and juice composition. A series of multivariate analyses were sequentially performed, and five highly-discriminant traits were identified as the most discriminant ones (shoot internode length, berry weight, berry elongation, 100-seed weight and juice titratable acidity). The clustering of the cultivars according to these five traits revealed that some local Syrian cultivars share similitude with some worldwide grown cultivars, suggesting their potential as new genetic resources for the Electronic supplementary material The online version of this article (doi:10.1007/s10722-017-0561-x) contains supplementary material, which is available to authorized users. S. Khalil  J. Tello (&)  A. Forneck Division of Viticulture and Pomology, Department of Crop Sciences, University of Natural Resources and Life Sciences Vienna (BOKU), Konrad Lorenz Straße 24, 3430 Tulln, Austria e-mail: S. Khalil  F. Hamed Department of Horticulture Science, Faculty of Agriculture, Damascus University, Damascus, Syrian Arab Republic development of new high-quality table grape varieties, and indicating the needing of specific preservation programs aimed to avoid the loss of endangered genetic local resources. Besides, the statistical multivariate pipeline followed in this work is proposed as an efficient one for the selection of ampelographic traits for the discrimination of grapevine cultivars. Keywords Conservation  Descriptors  Genetic resources  Phenotypic diversity  Syrian Arab Republic  Vitis vinifera L. Introduction Grapevine (Vitis vinifera L.) is one of the most ancient cultivated fruit trees in the world. It is suggested that the earliest domestication processes and the beginning of winemaking took place in the region comprised between the Black and Caspian seas between the seventh and the fourth millennia BC (McGovern et al. 1996). This fact is supported by archeological findings reporting the recovering of grape remains (mainly seeds, but also grape skins and grapevine wood) and jars for wine storage in settlements of Anatolia, the Zagros mountains of Iran, the Caucasus and northern Syria (McGovern et al. 1997). Climatic and geological conditions on northern Syria were specially well suited for viticulture development, with hills and 123 1842 mountains providing the cool winters and long hot summers required for optimal grape ripening (Lutz 1922; Unwin 1991). Consequently, relevant centers for grape cultivation, wine making and wine trading arose in this region (Maraqten 1993), and textual and artistic evidences indicate that Syrian wines were highly appreciated in antiquity because of their excellent quality (Unwin 1991). As a result, ancient commercial Syrian cities like Palmyra made of local wines an important commodity for trading with close and distant regions (Lutz 1922; Maraqten 1993), an activity that extended during Greek and Roman periods (Zuchowska 2013). Later on, Muslim influence led to the abandonment of winemaking practices, and farmers focused on the growing of local grape cultivars for fresh fruit and raisins production, which are still cultivated by the Syrian population. Nowadays, the Syrian Arab Republic has a gross production of ca. 200,000 tonnes in 2014 (FAOSTAT) from 46,000 ha of vineyards spread all along the country, particularly in southern and central regions like Homs, Al Suwayda, Al Qunaytirah, Dara’a, Aleppo, Damascus, Hama and the coastal area (Mslmanieh et al. 2006). Local Syrian grapevine resources are interesting reservoirs for grape quality and possible stress resistance traits. So, their preservation and evaluation is paramount for understanding grapevine natural diversity and for the selection of plant material for modern grapevine breeding programs (Abdullateef et al. 2011). Nonetheless, these traditional local resources are threatened by various anthropogenic pressures and by their replacement by selected international cultivars. Conscious of the relevance of preserving these invaluable local genetic resources, and looking for the development of better adapted new grapevine cultivars and clones, the Arab Center for the Studies of Arid Zones and Dry lands (ACSAD) established in 1996 a Gene Bank collection in the Jillin Research Station after the prospection of locally-grown traditional varieties. Despite its wide interest, and in contrast to local genetic resources from nearby regions (Aroutiounian et al. 2015; Basheer-Salimia et al. 2014; Chalak et al. 2016; Drori et al. 2017; Ekhvaia et al. 2014; Ergül et al. 2002; Eyduran et al. 2015; Fatahi et al. 2003; Khadivi-Khub et al. 2014; Lamine et al. 2014), few local Syrian grapevine cultivars have been adequately described so far (Sawaf et al. 1976). 123 Genet Resour Crop Evol (2017) 64:1841–1851 Ampelography is the science for the identification of grapevines through the analysis of phenotypic traits. The Précis d’Ampélographie Pratique by Galet (1952) can be considered the reference manual in ampelography, and many of the descriptors described there have been adopted by international organizations (like IPGRI and OIV) for the official description of grape varieties and Vitis species. Although the use of molecular markers is recommended for grapevine identification, ampelography provides relevant morphological and agronomical information for characterization studies, breeding programs and conservation purposes (Barth et al. 2009; Garcı́aMunoz et al. 2011; Lamine et al. 2014). Nevertheless, the use of diverse (but sometimes highly correlated) ampelographic descriptors comprising shoot, leaf, cluster and berry traits yield large datasets that need to be treated in a proper way. The sequential use of univariate and multivariate statistical approaches has been proposed to aid in the selection of the most informative ampelographic characteristics for the classification of different grapevine varieties from a certain region. In this regard, Lamine et al. (2014) indicated that the number of ampelographic traits contributing to the efficient characterization of a series of Tunisian autochthonous varieties could be reduced from 70 to 12, and Garcı́a (...truncated)