VARIABILITY AND HERITAGE OF MORPHOPHYSOLOGICAL SYMPTOMS IN BIOLOGICAL PLANTS IN THE PROCESS OF SELECTION OF SUNBULL PLANTS

The total water content, dominance and flexibility coefficients in the leaves of F1- F2- F3 plants of hybrid combinations obtained from simple and complex hybridization to create a water-resistant selection material of sunflower from oilseeds were studied. This study showed that this trait is inherited differently in simple and complex F1, F2 and F3 hybrids under different water regime conditions, with F2 hybrid combinations varying depending on the dominance coefficients and water supply conditions in hp as well as the composition of the parent forms of hybrids. The plants showed that the total amount of water in the leaves depends not only on the conditions of water supply but also on the genotypic composition KEYWORDS: Sunflower, morphophysiological, heredity, hybrid, drought tolerance, yield, seed core, ripening, cohesion, variability, hybridological analysis.

The study of the water regulation mechanisms in the winter bread wheat varieties under an acute drought

Water regime of plants, characteristic of a certain variety, largely determines the resistance of plants to drought. Drought affects, first of all, such indicators as water absorption capacity, water retention capacity, water deficit and changes in total water content in the process of ontogenesis. Studying and taking into account a number of parameters of water regime can significantly increase the reliability of the assessment of plants for drought resistance. The purpose of the current study was to investigate the water regime of the winter bread wheat varieties under an acute drought and to select promising samples for breeding for drought resistance. The objects for the study were 7 winter bread wheat varieties developed by the FSBSI “Agricultural Research Center “Donskoy”. The study was carried out on the experimental plot (zasushnik) of the laboratory for plant physiology under an acute drought of 30% PV in 2017–2019. According to the study results, there have been identified the varieties ‘Zhavoronok’, ‘Volnitsa’ and ‘Volny Don’, which were characterized by the largest increase in water-absorbing capacity (from 40.0 to 41.1%); by a minimum increase in water deficit (1.3–2.1%); by the smallest decrease (3.2–3.8%) in the total water content in fibers due to adaptability to water stress conditions in spite of increasing drought. There has been recommended to introduce these samples into the breeding process aimed at developing drought-resistant winter bread wheat varieties.

Total and Fractional Composition of Water in Pear Leaves Depending on the Optimised Fertiliser

The water content in tissues is an important indicator of the physiological state of the plant and is of great importance in the comparative assessment of their cultivation measures that increase productivity. One of such measures is rational fertilisation of plantings, which determines the relevance of the study. The purpose of the study was to establish the effect of optimised fertiliser on the water content in pear tree leaves and the fractional composition of water during stressful growing periods. One of the critical problems is drought, which negatively affects the growth and productivity of plantings. Under such conditions, the turgor of plant cells decreases and the passage of biochemical and physiological processes in the plant slows down. The paper considers the results of studying the water regime of leaves (the content of total, available, and inaccessible moisture) of pear varieties Konferentsia and Osnovianska on vegetative rootstock Quince A grown using optimised fertiliser in nonirrigated plantations. The study was conducted in 2011 and 2018 in a certified educational and research laboratory of the Uman National University of Horticulture. It was found that during the age periods of growth and fruiting, there was a change in the total water content in the pear leaves of the studied varieties. Leaves from pear trees of the Konferentsia variety had a higher water content compared to the Osnovianska variety. Fertiliser options increased the total water content in the leaves, which had a positive effect on the condition of the trees. It was found that at the beginning of the growing season, the free water content in the leaves of pear varieties Konferentsia and Osnovianska was higher, while it significantly decreased in the middle of the season. The bound water content was higher in all studied options. Under stressful situations (drought, temperature increase), fertiliser application had a positive effect on the water content in the leaves of both studied pear varieties. The practical significance of the study is to recommend the production of a rational fertiliser system for nonirrigated pear plantations in different age periods of growth and fruiting, which positively affected the water content in leaves and the fractional composition of water during stressful periods of cultivation

Indicators of the water regime of some varieties of chrysanthemums in the conditions of the South Ural

In introduction studies, it is of great importance to determine how favorable the water balance of the studied species is under given environmental conditions. The aim of the research was to study the water regime of some varieties of chrysanthemums in the conditions of the Southern Ural. The study was conducted in 20182020 on the basis of the South-Ural Botanical Garden-Institute of the Ufa Federal Research Centre of Russian Academy of Sciences. The objects of the study were 23 varieties of Chrysanthemum hortorum Bailey. In the course of the research, the total water content, water-holding capacity, the content of mobile moisture, water deficit, and sublethal water deficit were determined. The analysis of water regime indicators is based on the method of artificial wilting (V.N. Tarenkov, L.N. Ivanova) and the method of saturation of plant samples (V.P. Moiseev, N.P. Reshetsky). Sublethal water deficit was determined by the method of T.K. Goryshina, L.I. Samsonova, modified by N.I. Bobrovskaya. The calculations were carried out by standard methods using statistical packages of the Microsoft Excel 2003 and the Agros 2.13 program. The studies made it possible to determine the value of the sublethal water deficit (28,4%) for the varieties of chrysanthemums in the conditions of the Bashkir Ural. It was found that the studied varieties during the growing season did not experience such a moisture deficit in the tissues that could lead to irreversible damage to the assimilating organs. Our experiments showed that chrysanthemum varieties in the Bashkir Cis-Ural under the same soil-climatic and agrotechnical conditions had the following range of indicators of total water content 70,090,4% and water-holding capacity 19,0064,6%. The analysis of variance revealed significant differences between water-holding capacity and the content of mobile moisture by varieties, the share of influence was 27,8531,71%. As a result of the correlation-regression analysis, the authors revealed a direct dependence of the indicators of mobile moisture content on the total water content, and an inverse one on the indicators of the content of mobile moisture and water-holding capacity.