Identification of Sustainable Ecotypes of Haloxylon Aphyllum (Minkw.) Iljin. and the Creation of Seed Plantations

Abstract

The results of studies on the growth and development of black saxaul (Haloxylon aphyllum (Minkw.) Iljin.) of various geographical origins and its relationship to the main environmental factors in order to identify the most promising climatypes for the creation of a seed base are provided. By testing 19 climatic ecotypes of saxaul, it was established that, in the first year after planting in the experimental plot, they suffered from frost, which was due to insufficient lignification of the annual growths of the southern climatic types. The preliminary permissible boundaries for zoning of saxaul seed material for the arid zone have been identified. The main growth indicators of saxaul during the growing season were analyzed, which made it possible to identify the earliest swelling of buds in Zaisan saxaul (Mongolian ecotype), as well as in saxauls introduced from Kazakhstan, Baskunchak, and Kharabali (Astrakhan oblast). The growth processes of saxaul continue throughout the summer period, but in the hottest years, growth is also observed in September. It has been established that the growth energy of saxaul increases with increasing air temperature, which is especially noticeable in southern climatic types. The dependence of shoot growth energy on the amount of precipitation in representatives of this species has not been noted. The highest water regime indicators were noted in saxaul introduced from Dosang (Astrakhan oblast), which characterizes them as the most drought-resistant biotypes. The crops created from northern reproduction seeds showed the highest frost resistance. The adaptation of saxaul to new growing conditions is demonstrated by its good fruiting, growth in height, increase in the diameter of the trunk and crown, and high biomass indicators. Damage to experimental plants by pests and diseases was noted by the authors only during dry and hot periods, mainly in saxaul climatypes from Kazakhstan and introduced species; no damage was noted in southern climatypes. Observations of the state of the saxaul in the conditions of the Astrakhan Trans-Volga region showed the prospects of creating its seed base in geographical cultures.