Peculiarities of the phenological development of <i>Malus</i> P. Mill species in the conditions of the steppe zone of the southern urals

Abstract

The article presents the results of phenological observations of five-year-old trees of introduced species and forms of apple trees. The research was conducted in the Orenburg branch of the Federal Horticulture Research Center for Breeding, Argotechnology and Nursery in 2019-2021. Phenological studies were carried out according to the methodology of G. N. Zaitsev, statistical data processing was carried out using the methods of G. N. Zaitsev and B. A. Dospekhov. Data on the passage of 10 phenological phases were used (bud opening, beginning of flowering, end of flowering, end of shoot growth, lignification of shoots, beginning of fruit ripening, end of fruit ripening, autumn leaf coloring, beginning of leaf fall, end of leaf fall). In variable weather and climatic conditions during the growing season, it was found that the timing of the onset of the main phenological phases directly depends on the amount of accumulated positive temperatures, in particular, for the beginning of the growing season, this parameter is 245.2-304.7°C; for the beginning of the flowering phase — 630-609.4°C; the end of shoot growth was accompanied by the accumulation of positive temperatures from 2 152.8 to 2 398°C; at the end of fruit ripening, the sum of positive temperatures was 2 736.3-3 386°C; the beginning of leaf fall corresponds to the sum of positive temperatures from 2 873.9 to 3 200.8°C. In the conditions of the study, the duration of the growing season is 169-176 days, which is a short growing season. Weather and climatic conditions had a significant impact on the processes of active growth and flowering, the genotype of the studied species and forms caused the processes of fruit ripening, lignification of shoots, leaf fall. The duration of the shoot growth period is in direct correlation (r = 0.74-0.81) with the hydrothermal coefficient. The main decorative periods, including flowering, fruit ripening, and the period of autumn coloring, depend to varying degrees on both genotypic characteristics and meteorological conditions in the growing area.