HEAT RESISTANCE AND DROUGHT RESISTANCE OF RED RASPBERRY IN CENTRAL RUSSIA (ON THE EXAMPLE OF THE OREL REGION)
The resistance of red raspberry plants to drought in the field conditions and hyperthermia (heat resistance) by heat shock method was determined in the laboratory of physiology of fruit plant resistance and in the field conditions of the laboratory of berry breeding and variety investigation at VNIISPK. In the laboratory conditions, the following indicators of water regime were studied: hydration of leaf tissues, water loss, water shortage and restoration of water balance. As a result of the studies, the negative effect of high temperatures on the raspberry plants was revealed, which was expressed in lowering the overall hydration of leaves and increasing water deficit. Raspberry varieties with maximal degree of heat resistance were revealed: Lazarevskaya and Espe. Varietal features of drought resistance of raspberry plants were determined by the field method. In the process of the work, damage to leaves, their shedding, as well as withering and shedding of fruits were taken into account. Drought under field conditions in the most affected the raspberry varieties, having a large leaf mass, i.e. extensive evaporating surface. Maximum damage was noted in the varieties Beglyanka, Meteor, Balzam, Zhuravlik, Kokinskaya, Kaskad Bryansky, Volnitsa, Arta, Jvars and Espe (2.0-2.5 points). The lowest degree of damage to the leaf apparatus in an average of three years of the research was revealed in the varieties: Sputnitsa, Skromnitsa, Peresvet, Rannya Zarya, Fantasia, Maroseyka, Lazarevskaya and Espe-within 0.5-1.0 points. According to the totality of the studied indicators of the water regime, Lazarevskaya and Espe were identified as red raspberry varieties with the highest potential of heat resistance. After heat stress, the varieties Arta, Ivars, Maroseyka, Rannya Zarya and Fantasia restored hydration of leaf tissues at a relatively high level, but were characterized by increased water loss and water deficiency.