Fruit growing
and viticulture of South Russia

Annotation

The research is devoted to the study of the influence of spring period low positive temperatures on the peculiarities of the apple trees winter varieties development in plantings of different type to substantiate the possibility of assessing the degree of their resistance to an unfavorable factor and agrotechnical approaches to its improvement. The laboratory and field experiments (2021-2022) were carried out in traditional and organic apple tree plantations of the third and fourth age periods that were laid down in the experimental training farm �Kuban� of the Kuban State Agrarian University (leached chernozem soils). According to the observations results, in the spring months of recent years in the southern region of Russia, a manifestation of hypothermia was noted, coinciding with the passage of the VI (micro- and macrosporogenesis) � VIII; IX (completion of gametogenesis, flowering and fertilization) stages of organogenesis in apple plants. The resistance of apple trees (Liberty, Florina varieties) to the action of low positive temperatures is determined by the ability of the plant organism to restrain the development of generative buds when unfavorable conditions occur. Plant stability manifestation is promoted by the use of the organic garden management system that ensures maximum implementation of self-regulation mechanisms of its components. At the same time, within the framework of traditional plantings, apple trees of various varieties (for example, Kubanskoe bagryanoe, Renet Simirenko) are less able to withstand adverse effects. It is determined that the application of spring foliar top dressing with organic fertilizer �Chelate Antistress� against the background of the manifestation of the temperature stress factor optimizes the photosynthetic activity of plants and the distribution of plastic substances between vegetative growth and the process of productivity formation, leading to a sharp weakening of the first � third waves of the forming ovaries and fruits falling, and as a result, a significant (20-28 %) increase in the economic yield and a decrease in the periodicity of fruiting.