Posylaeva O. Adaptive properties of soybean samples on the heat and drought resistance and selection of sources for breeding

Object: drought resistance and heat resistance as adaptive traits and their influence on expression of valuable parameters of modern soybean specimens under different field and simulated growing conditions of vegetationand and selection of valuable breeding sources. Objective: identification of adaptive traits of modern soybean specimens, in particular tolerance to heat and drought, selection of valuable genotypes to form a collection of sources for further use in breeding programs to create new high-yielding varieties. Methods: field, vegetation-field (method of simulated drought), laboratory, breeding, statistical methods. Novelty: An important scientific task to establish breeding value of modern adaptive properties of soybean specimens in terms of resistance to abiotic stress factors and to iidentify valuable genotypes for their subsequent use in breeding programs has been solved. The research differs from the previously known results by the latest approach on how to identify sources of resistance to heat and drought combined with valuable economic traits. Results: Seventeen soybean specimens with high drought resistance at early developmental stages, 14 heat-resistant forms and three reference specimens of heat resistance were identified under laboratory conditions. Under field and simulated drought conditions expression of valuable traits in 83 soybean specimens was studied; 16 breeding-valuable genotypes were selected as source material to increase resistance to heat and drought; 7 sources with high protein content and 12 sources with high oil content were chosen. Patterns of protein and oil accumulation, dependence of heat resistance index and type of performance formation on conditions of growing specimens were established: under stress, high performance of specimens is formed due to increased numbers of pods and seeds per plant. Specimens with high resistance to heat and drought were selected: Soyer 345, Sonyachna, Pripyat; the variety Galі had very high resistance to heat and drought. Degree of implementation: A working collection "According to the Degree of Resistance to Heat and Drought" was formed and registered in the National Center of Genetic Plant Resources of Ukraine (certificate number 161 dd 09/12/2014) based on 10 traits and 96 levels of their expression. Four drought-tolerant soybean specimens were registered in the National Center of Genetic Plant Resources of Ukraine (certificate numbers 1196-1199 dd 09/12/14). A method of laboratory heat testing of soybean specimens was improved (utility model patent number 93263 dd 25/09/2014). Thirty five soybean specimens were given to Kharkiv National Agrarian University named VV Dokuchaev (reference number 512/01-22 dd 27/03/2014) for use in the educational process. To expand and optimize breeding process, the research results were implemented in and the sources selected (49 pcs.) were transferred to the following research institutions: Institute of Oil Crops of NAAS (reference number 892 dd 08/08/2014), Plant Production Institute named after VYa Yuriev of NAAS (reference number 1/2a-21/834 dd 11/09/2014), Institute of Selection and Genetics - the National Center of Seed Studies and Variety Control of NAAS (reference number 12/868 dd 11/09/2014). Scope of implementation: breeding institutions.