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Evidence of Resistance to the Downy Mildew Agent Plasmopara Viticola in the Georgian Vitis Vinifera Germplasm

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Evidence of Resistance to the Downy Mildew Agent Plasmopara Viticola in the Georgian Vitis Vinifera Germplasm Vitis 55, 121–128 (2016) DOI: 10.5073/vitis.2016.55.121-128 Evidence of resistance to the downy mildew agent Plasmopara viticola in the Georgian Vitis vinifera germplasm S. L. TOFFOLATTI1), G. MADDALENA1), D. SALOMONI1), D. MAGHRADZE2), P. A. BIANCO1) and O. FAILLA1) 1) Dipartimento di Scienze Agrarie e Ambientali, Università degli Studi di Milano, Milano, Italy 2) Scientific – Research Center of Agriculture, Tbilisi, Georgia Summary ability during late spring and summer usually prevent the spread of the disease (VERCESI et al. 2010). The control of Grapevine downy mildew, caused by Plasmopara downy mildew on grapevine varieties requires regular appli- viticola, is one of the most important diseases at the inter- cation of fungicides. However, the intensive use of chemicals national level. The mainly cultivated Vitis vinifera varie- becomes more and more restrictive due to human health ties are generally fully susceptible to P. viticola, but little risk and negative environmental impact (BLASI et al. 2011). information is available on the less common germplasm. Damages due to P. viticola could be reduced by using The V. vinifera germplasm of Georgia (Caucasus) is char- resistant grapevine varieties. The breeding programs are acterized by a high genetic diversity and it is different usually carried out by crossing V. vinifera with resistant from the main European cultivars. Aim of the study is species and in particular with American Vitaceae that co- finding possible sources of resistance in the Georgian evolved with the pathogen. The first generation hybrids, autochthonous varieties available in a field collection in obtained from the end of the XIXth to the beginning of the northern Italy. The resistance levels to P. viticola were XXth century, were unsuitable for the production of high estimated both by experimental inoculations and by quality wines, due to their unpleasant foxy aromas coming disease assessment in field conditions in a multi-year from the American species of the Vitis genus (EIBACH and activity. Of the 93 tested accessions, 'Mgaloblishvili N' TÖPFER 2015). Nowadays, thanks to numerous backcrossing showed a constant resistant behaviour, by reducing the cycles, the last generation breeding varieties possess resist- disease severity and the pathogen sporulation. High ant characteristics of the American species and qualitative levels of leaf hair density did not always associate with characteristics similar to those of V. vinifera cultivars (DI reduced disease gravity in experimental inoculations, GASPERO and FORIA 2015). However, finding sources of re- confirming that this kind of preformed barrier is not sistance in V. vinifera could be a great innovation, because it completely efficient in preventing pathogen infections. could really simplify the breeding programs originating new varieties with the quality levels required for wine production. K e y w o r d s : grapevine; disease resistance; disease Interesting results concerning the European wild grape, a incidence. subspecies of the V. vinifera species, have been recently found (SCHRÖDER et al. 2015). The V. vinifera species comprises cultivated (V. vinif- Introduction era subsp. vinifera) and wild (V. vinifera subsp. sylvestris Gmelin) subspecies, originally dispersed from western Asia Plasmopara viticola (Berk. & M. A. Curtis) Berl. & to Europe (ZOHARY and HORF 2000). At present, more than De Toni is a biotrophic pathogen which causes downy 12,000 accessions are recorded as individual cultivated vari- mildew to members of the family Vitaceae, in particular to eties in Europe (Vitis International Variety Catalogue-VIVC; the cultivated species Vitis vinifera L. (BELLIN et al. 2009). http://www.vivc.de/index.php). The origin of most of them P. viticola was fortuitously introduced in France from North is still questionable due to: the existence of several putative America during the nineteenth century and rapidly spread domestication centers, dispersed in all the distribution area across Europe (GALET 1977). The pathogen infects all green of the wild progenitor; exchange of plant material among parts of the plant causing, in favourable weather conditions, countries; and possible crossing among locally domesticat- extensive losses in grape yield (YU et al. 2012). The dam- ed varieties and grapes imported from abroad. Georgia in ages caused by the pathogen can lead to quantitative losses, the South Caucasian region, is considered one of the most by infecting inflorescences and bunches, and to qualitative important primary centers of domestication of cultivated losses, by causing an early defoliation of the plant. grapevine, in the larger area comprising Oriental Anatolia, Severe epidemics of downy mildew usually occur in Syria and Northern Mesopotamia, where the first viticulture temperate regions, characterized by grapevine vegetative emerged, towards the middle of the VI millennium BC seasons with frequent rainfall and moderate temperatures. (FORNI 2012). Actually paleobotanical and archaeological On the contrary, high temperatures and reduced water avail- remains attesting the first development of the vinicultural Correspondence to: Dr. S. L. TOFFOLATTI, Dipartimento di Scienze Agrarie e Ambientali, Università degli Studi di Milano, Milano, Via Giovanni Celoria 2, 20133 Milano, Italy. E-mail: [email protected] © The author(s). This is an Open Access article distributed under the terms of the Creative Commons Attribution Share-Alike License (http://creative-commons.org/licenses/by-sa/4.0/). 122 S. L. TOFFOLATTI et al. production and grapevine domestications have been found in some interesting Georgian varieties showed a high level Southern Caucasus; moreover, the region is rich in grapevine of resistance to P. viticola in experimental inoculations diversity and wild grapevines are widely present in the area (BITSADZE et al. 2015). (MAGHRADZE et al. 2012a). The main objective of the study was searching possible The evaluation of Georgian grapevine germplasm is sources of resistance to P. viticola in Caucasian V. vinifera interesting for different reasons. This germplasm comprises a germplasm coming from Georgia and cultivated in a field very wide range of cultivars (525 according to KETSKHOVELI collection in northern Italy by combining two approaches: et al. 1960) with high genetic variability (DE LORENZIS et al. experimental inoculations of leaf discs and evaluation of the 2015) and various ampelographic characters, agronomical disease incidence in vineyard. traits and phenological diversity (MAGHRADZE et al. 2012b). The viticultural and the enological features of this genetic material are also very different from Western European Material and Methods material (IMAZIO et al. 2013) and interesting because of their possible cultivation for innovative wine quality profiles, P l a n t m a t e r i a l : The 94 Georgian grapevine which could be different compared to wines from Western varieties used in this study (Tab. 1) are grown in in a collec- cultivars. There is also an interest in possible sources of tion vineyard established in 2006 at the Regional Research useful genes for breeding programs for qualitative char- Station of Riccagioia in Lombardy region of northern Italy. acters and/or for tolerance to biotic and abiotic stresses They are all V. vinifera varieties native to Georgia (South (MAGHRADZE et al. 2012b, QUAGLINO et al. 2016). Indeed, Caucasus region) apart from one: a Vitis x labruscana L.H. Table 1 List of Georgian varieties in relation to their region of origin, berry colour and density of the hairs between the veins on the lower side of the leaf ID Name of variety Region of origin Berry colour* Hair density** L21A Okroula Kakheti B 3 L21B Tsnoris Tetra Kakheti B 3 L21C Kurkena Kakheti B 3 L21D Akhmetis Shavi Kakheti N 3 L21E Saperavi Grdzelmtevana Kakheti N 3 L21F Zakatalis Tsiteli Kakheti N 3 L22A Mgaloblishvili Imereti N 7 L22B Marguli Sapere Imereti N 5 L22C Gabekhouri Tsiteli Imereti N 7 L22D Endeladzis Shavi Imereti N 3 L22E Mtsvane Onidan Ratcha B 5 L22F Usakhelouri Ratcha N 3 L23A Khushia Shavi Imereti, Guria N 7 L23B Orona Guria N 5 L23C Ikaltos Tsiteli Kakheti N 7 L23D Okhtoura Kakheti N 7 L23E Kistauris Saghvine Kakhuri N 5 L23F Vertkvichalis Shavi Imereti N 5 L24A Satsuravi Adjara N 7 L24B Khrogi Ratcha N 3 L24C Zakatalis Tetri Kakheti B 5 L24D Mtsvivani Mskhvilmartsvala Kakheti B 3 L24E Jghia Kakheti N 5 L24F Chinuri Kartli B 3 M21A Ghvinis Tsiteli Kakheti N 3 M21B Kharistvala Shavi Kakheti N 3 M21C Tkupkvirta Kakheti N 3 M21D BudeshuriTsiteli Kakheti N 3 M21E Buera Kakheti B 3 M21F Goruli Mtsvane Kartli B 7 M22A Zerdagi Samegrelo N 7 M22B Paneshi Samegrelo N 5 M22C Chkhucheshi Samegrelo B 3 M22D Chkhaveri Guria N 7 M22E Kamuri Shavi Guria N 5 M22F Jani Bakhvis Guria N 5 M23A Tkbili Kurdzeni Kakheti N 7 M23B Kuprashviliseuli Imereti N 7 M23C Dzelshavi Obchuri Imereti N 3 Resistance to Plasmopara viticola in the Georgian Vitis vinifera germplasm 123 Tab. 1, continued ID Name of variety Region of origin Berry colour* Hair density** M23D Mirzaanuli Kakheti B 3 M23E Chkhikoura Imereti B 3 M23F Kapistoni Tetri Imereti B 3 M24A Asuretuli Shavi Kartli N 3 M24B Tavkara Kakheti N 7 M24C Argvetula Imereti N 7 M24D Vitis x labruscana Georgia N 7 M24E Ananura Kartli N 3 M24F Tchvitiluri Samegrelo B 7 N21A Gorula Kartli B 3 N21B Tita Kartlis Kartli B 3 N21C Adreuli Tkhelkana Kartli N 5 N21D Shavkapito Kartli N 5 N21E Ghrubela Kartlis Kartli B 3 N21F Buza Kartli N 5 N22A Otskhanuri Sapere Imereti N 7 N22B Orbeluri Ojaleshi Lechkhumi
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