Успадкування гібридами F1 ячменю ярого стійкості до біотичних чинників та окремих елементів продуктивності

Abstract

Genetic/breeding improvement of varieties is an effective method to increase yield capacity, resistance to abiotic and biotic factors of the environment and energy efficiency of crops, including barley. Knowledge of variability laws of valuable traits and their inheritance by offspring upon hybridization helps optimal selection of pairs to cross and to receive preliminary information from earlier hybrid generations about a possible final result. Targeted search for patterns of morpho-formation in hybrid populations and emergence of new biotypes enrich the applied genetics of spring barley, extend its methodological potential and allow the breeding process to be transferred to the scientific foundations of programming and forecasting. The article presents the results of studying the inheritance patterns of barley spring resistance to biotic factors and individual components of the yield structure by degrees of their phenotypic dominance in hybrid barley populations. The experiments were carried out in the field nurseries of the scientific crop rotation of the Institute. Different methods were used: phytopathological (creation of provocative backgrounds, records of the plant affection); breeding (hybridization, individual selection to develop starting material); statistical (assessment of the degree of phenotype dominance). In order to develop resistant staring material, sources of resistance to diseases and pests, which were singled out from previous studies, were involved in hybridization in 2016. Selecting couples for crossbreeding, we took into account the levels of prevalence, development intensity of disease and damage as well as abundance of a pest during three years against a strong provocative background. The trait of resistance to diseases and pests can be expressed in varying degrees in different years, depending on cultivation conditions and infectious load, as a rule, under extreme conditions for plants. Such conditions ensure complete or almost complete affection and damage of all susceptible plants in the population by a harmful organism. The weather conditions in 2014-2016 were favorable for the development of Helminthosporium spot diseases and grass fly-induced damage. In 2017, seven F 1 hybrid combinations and F 2 hybrid seeds were obtained to create lines that are resistant to biotic factors with high values of valuable economic characteristics. The inheritance patterns for individual components of the yield structure were investigated in these hybrid populations, and the degrees of their phenotypic dominance were deduced. From records in F 1 hybrids, the degrees of dominance of the resistance and performance traits were measured. Therefore, to study the inheritance of the above-mentioned traits, F 1 hybrid plants of spring barley and their parents were analyzed, and the degrees of dominance were deduced. The inheritance types of valuable economic characteristics in our study were different, which largely depended on a crossing combination. Positive overdominance for the traits of resistance to Helminthosporium spot diseases, grass flies and plant performance was detected for most of hybrid combinations (42,9-85,7 %). Significant variations in the degree of phenotypic dominance (from negative overdominance to positive overdominance) were noted for 1000-seed weight, indicating a complex nature of the genetic determination of this trait in barley and that the seed weight is determined by different types of gene interactions in hybrid organisms. In our study, positive overdominance was detected for all of the investigated features in 28,6 % of hybrid combinations, indicating a chance to distinguish valuable genotypes, which would be superior to parents, in subsequent generations. The nature of the inheritance of the valuable trait of 1000-seed weight was found to be different, which largely depended on a crossing combination. We singled out combinations in which augmentation in expression of positive changes in subsequent hybrid generations can be expected: Talovskiy 9 / Krok, Krok / Talovskiy 9, Naran / Modern, Natali / Hatunok, and Hatunok / Natali. There is a probability to find more productive biotypes in subsequent generations of these combinations with further individual selection on a provocative background, which will make it possible to develop both resistant and productive starting material for spring barley breeding. Basing on the study results, we carried out selections from the best hybrid combinations for further studies and creation of disease-resistant and productive starting material for spring barley breeding.