Inheritance by F1 sunflower hybrids of resistance to powdery mildew in conditions of provocative field background

Abstract

Goal. To study the resistance to the pathogen of powdery mildew of sunflower hybrid lines, to determine the nature of its inheritance in F1 hybrids, and the level of manifestation of valuable economic features in stable hybrid combinations. Methods. Field — to obtain F1 hybrids, determine the hit of lines and hybrids with powdery mildew, and study the economic characteristics of hybrids; laboratory — to determine the oil content in the seeds, and the mass of 1000 seeds; mathematic — to determine the degree of phenotypic dominance (hp) of resistance to powdery mildew, and assess the reliability of the research results. Results. Field studies were conducted in 2020–2025 based on the experimental field of the 4-field crop rotation of V.Ya. Yuriev Institute of Plant Production of NAAS. In the conditions of 4-field crop rotation, the distribution of powdery mildew of forms I and II, on average, in the studied lines-parental components was 20.5%. The stability of the lines varied within 3–9 points. According to the degree of dominance, the inheritance of resistance to the causative agent of the disease was carried out in 4 types: positive superdomination (20% of hybrid combinations), partial positive dominance (53%), intermediate inheritance (20%), and partial negative dominance (7%). At crossing lines with stability score 9 and lines with stability scores 3 and 5, partial positive dominance and positive superdomination of stability were established, which in such hybrid combinations was at the level of 92.1–100%. For example, the yield of seeds of the hybrid Vyrii resistant to powdery mildew in a demonstration test exceeded the average yield in the experiment by 28%. Conclusions. A high infectious background of fake powdery mildew of sunflower was created in the conditions of 4-field crop rotation, which contributed to the differentiation of the line-parental components and hybrids in terms of resistance to the causative agent of the disease. It was found that resistance to powdery mildew dominated in the hybrid generation F1. Lines X 06135 V, X 06134 V, and Cx 777 A, even when crossed with an unstable parent component, provided very high resistance of F1 hybrids to powdery mildew.