Fruit growing
and viticulture of South Russia

Annotation

Micropropagation is a promising direction for obtaining a healthy, genetically homogeneous grape planting material. The efficiency of reproduction is determined by many factors, including the acclimatization of plants to natural environmental conditions. The difficulty of transferring in vitro plants to non-sterile conditions is associated with a number of physiological and anatomical features of in vitro plants, among which the low level of photosynthetic processes is of particular importance. The influence of various concentrations of sucrose in the culture medium and additives, simulating environmental stresses on the rates of photosynthesis of grapes during acclimatization, was studied. The content of sucrose 10g/l in the culture medium was the most optimal for the formation of the photosynthetic apparatus. Both low and high sucrose content in the culture medium negatively affected the formation of pigments and the efficiency of photosynthetic processes. The introduction of PEG and NaCl into the nutrient medium led to a decrease in the total content of pigments, the quantum yield of photochemical reactions, but increased the expression of RUBISCO activase. The use of ABA as part of the culture medium had a positive effect on the formation of pigments in grape plants during acclimatization. The effects of weak stresses on the photosynthetic parameters of grapes in in vitro culture and during the acclimatization period are identical to the effects of drought and salinity under natural conditions. At the same time, these types of influence have a positive effect on adaptive �anti-stress� reactions that prevent plant damage under ex vitro conditions, which ultimately increases the level of growth processes and the yield of seedlings during micropropagation of grapes.

Annotation

The search for reliable methods for assessing the resistance of grape varieties to heat and drought is relevant in connection with the increasing climate instability in the Anapo-Taman viticulture zone. The purpose of the work is to conduct electrophoretic separation of peroxidases in polyacrylamide gel in the leaves of various grape varieties, to identify varieties with increased resistance to heat and drought. The objects of research are grape varieties of various ecological and geographical origin: Kristall (control) � Euro-Amur-American origin; Dostoynyi, Krasnostop AZOS � Euro-American origin; Vostorg � Amur-American origin; Zarif � Eastern origin; Aligote � Western European origin. It was established that the qualitative and quantitative composition of peroxidase isoforms changed during the summer and had a varietal feature. In June, 4-6 isoforms were isolated for each particular variety, in August � 2-4 isoforms. The Kristall variety stood out for its especially high resistance to heat and drought during the summer, both in the field and under the influence of artificial high-temperature and water stresses. This was achieved due to the multiple isoform composition of peroxidases and the constancy of their composition in response to stress. Varieties Dostoynyi, Vostorg, are highlighted as highly resistant to heat throughout the summer. The heat resistance of varieties Krasnostop, Aligote, Zarif changed during the summer period. In relation to drought, the varieties Kristall, Dostoynyi, Vostorg showed high resistance in early and mid-summer. According to the appearance and disappearance of peroxidase isoforms, the drought resistance of varieties Dostoynyi, Vostorg, Krasnostop AZOS changed during the summer. Aligote and Zarif varieties during the summer period stood out as not drought-resistant. The obtained data can be used as diagnostic criteria for assessing the degree of heat and drought resistance of grape varieties in different months of the summer period in the conditions of the Anapo-Taman zone of the Krasnodar region for breeding purposes.

Annotation

The search for new promising pear varieties with high adaptation and production potential is an important aim of modern breeding for the southern regions of the Russian Federation. In present study, the results of the physiological characteristics of four pear varieties during the summerautumn season 2022-2023 are presented. Pear trees were planted in the territory of the Prikubanskaya fruit growing in the Krasnodar Region. Three varieties Leven, Lyuberskaya, Flamenco of Russian breeding and the American variety Devo were used. The pear leaves were selected three times during the summer months and in September. The content of soluble sugars and total phenols, as well as the activity of antioxidant enzymes � superoxide dismutase and peroxidase � were determined in the plant material. It was established that an increase of the level of the primary and secondary metabolites accumulation and an increase of enzymatic activity by ~20-75 % occurred in the hotter and drier 2023. The content of soluble sugars significantly increased to ~12.0 mg/g fresh weight in the leaves of the varieties Devo and Leven. The accumulation of phenolic compounds increased in all pear varieties by more than 30 % with values exceeding 27,0 mg/g fresh weight. The level of superoxide dismutase activity in 2023 averaged 13.4 unit/mg protein, which is slightly higher than the values of 2022. Peroxidase activity increased 2-4 times with maximum values of more than 8,0 unit/mg protein per min. in the varieties Leven and Lyuberskaya. In conclusion, the data obtained indicate that the drier and hotter conditions of 2023 were not critical for the normal growth and development of the studied pears varieties, but only initiated the activation of the defense antioxidant system in plant cells.