The article presents the results of research into a collection of peaches and nectarines cultivated at the Federal Scientific Research Center of the Russian Academy of Sciences in Sochi. The experiment was conducted in open ground, plot area is 0.5 hectares, planting pattern is 5x2.5m, 5x2, 5x1.5m. In 2019, the Center’s assortment was replenished with 28 variety-rootstock combinations of peach and nectarine based on eight varieties (Pamyat Simirenko, Redhaven, Zolotoy Yubiley, Osenniy Rumyanets, Obilny, Orion, Pyatnitsa 13, Silver Roma) of different ripening periods on four clonal rootstocks: Kuban 86, BP, Best, VVA. The physiological and biochemical characteristics of variety-rootstock combinations of peach and nectarine, resistant to abiotic factors in the humid subtropics of Russia, have been studied. The object of study is peach leaves. Physiological analyzes were carried out in the plant physiology and biochemistry department using classical methods: water deficiency of peach leaves was determined according to Pochinok; tissue hydration - according to Gunar; water holding capacity - according to Arland; dry matter - by drying in a drying cabinet to constant weight. Leaves were collected from June to August. Agricultural technology is generally accepted for peach culture. Brown forest soils. It has been established that the best varieties of peach and nectarine in terms of ability to retain water during the dry period are: Redhaven (AP), Pyatnitsa 13 (AP), Pyatnitsa 13 (Best), Pyatnitsa 13 (BP) with low water deficit (11.06-4. 78%) and high water-retaining system of leaves (64-76%). They were distinguished by an increase in the turgor of leaf tissues to 66.33-69.27%, which is considered a sign of plant adaptability to disturbances in the water-thermal regime.