Comparative study of the influence of the rootstock on the degree of drought resistance in the grapevine cultivar Kaylashki rubin

It was performed a comparative study on the drought resistance of the red wine cultivar Kailashki rubin, grafted on four different rootstocks. It was established that during the studied period 2017-2020 the tendency to significant warming and drought in Pleven region of Bulgaria was permanently outlined, expressed in increasing the values of the total temperature sum and reducing the total rainfall during the growing season. Under the specific climatic conditions for each year and on average for the period, in all studied cultivar-rootstock combination, water stress of different intensity was found. The performed statistical analysis of the data determines as reliable the differences in the values of the established water deficit as regards to the different rootstocks. Drought resistance, as a very important agrobiological characteristic, was the highest in the cultivar-rootstock combination Kaylashki rubin/110 Richter and the lowest in Kaylashki rubin/Berlandieri x Riparia SO 4 (control). The combination Kaylashki rubin/44-53 Malegue also appears to be very promising in terms of its response to the studied abiotic stress factor.