Drought Resistance of Cerasus vulgaris Mill. Cultivars Depending on Rootstock in the Right-Bank Part of the Western Forest-Steppe Region

Abstract

In the right-bank part of the Western Forest-Steppe, there has been an observed yearly increase in average daily summer temperatures, underscoring the importance of assessing drought tolerance in fruit crops, including cherries. This research aimed to identify the most drought-resistant cherry rootstock-cultivar combinations and the factors enhancing drought tolerance. The study focused on physiological indicators of water balance: water retention capacity, degree of turgor recovery, water deficit, and leaf tissue hydration Cerasus vulgaris Mill., which determine resistance to temperature stress. The research was conducted during 2022–2023 using laboratory-field methods at the Institute of Horticulture, NAAS, located in the right-bank area of the Western Forest-Steppe. The research subjects were various cherry cultivars – Igrushka, Lutovka, Balaton, Erdi Botermo, Nochka, Turgenevka, and a promising selection – D 36-25 on various rootstock forms (Prunus mahaleb L., Krymsk 5, V-2-180, V-2-230, V-5-88, Rubin), during peak water stress periods. Results indicated that most cherry rootstock-cultivar combinations exhibited high drought tolerance. The water deficit index for studied combinations ranged between 2.2–9.2%, with high and drought-resistant combinations showing values within 2.2–5.6%. Leaf tissue hydration in the studied combinations varied between 60.87–65.93% for cultivars and 60.23–64.19% for rootstocks. The water retention capacity of leaf tissue for most combinations indicated a 10.9% water loss after two hours, while certain cultivars showed an increase of 13.7%. After 4-6 hours, water retention capacity increased by 2.41-3.45% per hour. Turgor recovery in the studied combinations ranged between 40.3–52.7%. Factors influencing drought resistance in these cherry rootstock-cultivar combinations were also identified (weather and climatic factors accounted for 26.0%, cultivar, and rootstock forms for 17.0 and 9.0%, respectively, between climatic conditions and cultivars at 22.0%, and between rootstock forms and cultivars at 18.0%. The results demonstrated that all studied cherry rootstock-cultivar combinations are highly drought-resistant, with drought resistance primarily influenced by the compatibility between cultivar and rootstock and the growing conditions.