Neglected cultivars for the Mtskheta-Mtianeti region (East Georgia): ampelography, phenology, and agro-climatology

Georgia is an important source of grapevine intra-specific variability for viticulture. This biodiversity can be a suitable tool to face the challenge of climate change. Nevertheless, it is important to take into account the interaction between the interest genotype and the local environment, whose cli-mate is changing due to global heating. In this work, we put in relation the phenotypic behavior of some neglected Georgian cultivars ('Tabidziseuli', 'Daisi', 'Qvelouri', 'Bazaleturi Co-likouri') from the Mtskheta-Mtianeti Georgian region to the agro-climatology of the region itself. The phenological phases and the vegetation length of these four grape varieties were described, as well as their principal ampelographic characters. The impact of global heating on the agro-climatology of the Mtskheta-Mtianeti region has also been established, by com-paring the sum of active temperatures (>10 degrees C) of multi-years (1948-2017) with those calculated for the future scenario (2020-2050, temperature increase by 2 degrees C). Based on this comparison, three agro-climatic zones have been confirmed with in the region: dry subtropical, mountain and high mountain. The scenario of temperature increase by 2 degrees C in the next three decades will cause the sum of active temperatures to reach 3900-4000 degrees C in the dry subtropical zone, 3400-3500 degrees C in the mountain zone and 1900-2000 degrees C in the high mountain zone. Considering the vegetation length of the cultivars analyzed, it can be expected a shift of the most suitable sites for viticulture from the dry subtropical zone to the mountain area. High mountain seems not to be suitable for the cultivation of the studied cultivars. Given this environmental variability within the region, the increase in temperature will not suppress viticulture in Mtskheta-Mtianeti, if the real temperature does not exceed the level predicted by scenario.