The article presents experimental data on physiological and biochemical studies of stone fruit culture on the example of Persica vulgaris (Mill.) In the humid subtropics of Russia. The research has been carried out since 2011 in the Laboratory of plant physiology and biochemistry of the Subtropical Scientific Center of the Russian Academy of Sciences on peach varieties of different ripening periods grown in the humid subtropics of Russia. To identify any physiological changes in the body of

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... h plants during drought, especially in summer, comprehensive diagnostic studies of the water regime (leaf turgidity, determination of the thickness of the leaf blade, water deficiency) and pigment composition are carried out, characterizing the functional state of peach plants. Under unfavorable conditions, promising varieties have a higher ratio of chlorophylls to carotenoids, which confirms their more developed adaptive potential. Studies of this nature have been carried out in order to identify and select resistant peach plants among the studied varieties, which would correspond to the humid region of the Black Sea coast of the Krasnodar Territory. In the subtropical zone of our region, the issue of drought resistance has always been acute, since the impact of negative environmental factors (cool spring, accompanied by drizzling rains and a long summer shortage of air and soil moisture) on peach plants lead to a decrease in productivity and a deterioration in the quality of fruits, which makes their unsuitable and non-transportable. It has been found that among the tested plants, peach varieties Maycrest, Fayet, Larisa have been distinguished by high physiological indicators, such as: low water deficiency – 12,20–14,65%, leaf turgidity ­– 0,18 mm, saturation of leaf tissues within 70,12–79,21%, the content of carotenoids is 0,5–0,7 units, which is a confirming sign of their high resistance to the negative effects of weather conditions in the south of Russia.