The article presents the results of the laboratory investigation of the influence of high temperatures on water regime of red currant in Institute of Fruit Selection. It shows the dependence of water loss by leaves on the phenophase of plant development. High water loss by leaves occurs during the phase of ripening berries (July). Low water loss is noted during the active growth of shoots (June). Red currant genotypes: «Valentinovka», «Bayna» have a high percent of water loss in June and July. Genotypes «Shedraya», «Gollandskay krasnay», «Orlovchanka», «Dar Orla», «Selyanochka», «Osipovskay», «Belka» and «Jonker van Tets» have a low percent of loss water. The loss of water at the temperature shock is the important protective mechanism from over heat and death of plants. The results of the investigation of a degree of water restoration by red currant leaves in the periods of berry ripening and active growth of shoots are given. The most part of genotypes of red currant leaves have a high percent (>50%) of water restoration. Genotypes «Selyanochka» ,«Orlovchanka», «Dana», «Shedraya», «Belka» have a more 100% of water restoration. On the ground of the obtained results the following genotypes: «Belka», «Selyanochka», «Gollandskay krasnay», «Shedraya», «Orlovchanka», «Dar Orla», «Osipovskay» and «Jonker van Tets» are mostly heat resistant.

The article mentions that 113 peach hybrid forms resistance to drought, to leaf curl infection Taphrina deformans Tul. and powdery mildew Sphaerotheca pannosa Lev. var. persicae Woronich have been obtained in the result of their studying. One of the most important agronomic sigh is a drought- resistance. Elite forms assessment on this indicator has been carried out in the most drought year during the last50 years. 23 forms with high drought-resistance have been selected. The leaves curl and false mildew are considered to be the most harmful fungal diseases reducing the plants peach vitality and leading to their lethality. Infection assessment has been carried out according to the average annual dates, and in epidemic (epiphytotic) year with a maximum disease revealing. As a result 14 hybrid forms infected by low leaves curl and 16 – by false mildew have been selected. According to the varieties characteristics complex 15 ones have been selected. Most varieties identified by their drought-resistance have belonged to the North Chinese eco-geographic group (59,1%), by a low leaves curl infection (Taphrina deformans Tul.) to the Iranian eco-geographic group (64,3%); by the false mildew (Sphaerotheca pannosa Lev.) to the Northern Chinese eco-geographic group (54,3%). The selected varieties perform the interest as sources of important mentioned economic valuated characteristics and they can be used in breeding.