Assessment of the level of drought resistance of the group of seedless varieties of the collection of NSC «Tairov institute of viticulture and winemaking» on indicators of water-containing capacity of leaf tissues

Replenishment of the assortment of seedless varieties of Ukrainian selection is one of the tasks of breeders of NSC «IViV them. V.Ye. Tairov ». Climate change has exacerbated and increased the duration of droughts in spring and summer. That is why it is necessary to use in crosses the parent seedless component with a known level of drought resistance. According to the results of the research, the level of drought resistance of the group of seedless varieties of the ampelographic collection of the NSC «IViV im.V.Ye. Tairov «of different genetic and geographical origin was determined . Both intraspecific hybrids of Vitis vinifera and interspecific hybrids, which in their estimated genetic formula contain 3-4 species of Vitis, were studied. The study was based on determining the level of manifestation of the physiological mechanism of protection against temperature stress - the water-holding capacity of leaf tissues. Studying the content of different fractions of water (easily retained and bound) and changes in their ratio during the growing season made it possible to identify stress-tolerant varieties. The study was conducted in years with a high level of exposure to temperature stress, which increases the objectivity of the data. The obtained results confirmed the sensitivity to the lack of moisture supply of interspecific hybrids derived from varieties created with the participation of non-drought-resistant species Vitis amurensis. The research was aimed at identifying donor varieties with the sign of «drought resistance», namely varieties with high water holding capacity. Due to the impact of lack of moisture on the grape plant, samples were taken in critical phases - the phase of intensive growth of shoots, the phase of formation and growth of berries and the phase of completion of the growing season. A rather high level of drought resistance of intraspecific hybrids has been determined, which is explained by their origin from Central Asian varieties. However, the main feature of the breeding interest that they can pass on to offspring is seedlessness and product quality. In comparison with the control values, the varieties Attika and Flame seedless stood out. These varieties are recommended for use in the further selection process as sources and donors of a set of signs of selection interest, including the ability to withstand thermal stress and lack of moisture.