PHYSIOLOGICAL FEATURES OF PEAR VARIETIES IN THE TERRITORY OF THE KRASNODAR REGION

Abstract

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. Key words: PEAR, PRIMARY AND SECONDARY METABOLITES, ANTIOXIDANT ENZYME ACTIVITY