Genotype and seasonal conditions influence on the degree of phenotypic dominance of total bushiness during intraspecific hybridization of winter wheat (Triticum aestivum L.)

Wheat (Triticum aestivum L.) is an important grain crop in world agriculture. One of the main factors in increasing yield and stabilizing wheat grain production is the rational use of varietal resources that are competitive and suitable for the soil and climatic conditions of certain regions. In the experimental field conditions of the Scientific Research Center of the Bila Tserkva National Agrarian University in different meteorological conditions in 2018-2020 the highest average total bushiness among varieties (2.0 pcs. stems/plant) was formed in 2020. In 2018 and 2019, the total bushiness was slightly lower and amounted to 1.8 and 1.9 pcs. stems/plant respectively. During the research years, the total bushiness of the parental crossing components had a significant differentiation of 1.4-2.6 pcs. stems/plant. The total bushiness of the hybrids majority obtained in 2018-2020 (1.6-8.9 pcs. stems/plant) significantly exceeded the indicators of parental forms. The maximum average F1 indicator (6.1 pcs. stems/plant) was formed in 2019. The minimum total bushiness (3.7 pcs. stems/plant) was formed by hybrids in 2020. The research has established that the most common type of inheritance of total bushiness in 184 Агробіологія, 2024, № 2 agrobiologiya.btsau.edu.ua 2018-2020 was positive overdominance. Thus, when using early-ripening varieties as the maternal form, positive overdominance was established in 95.0% of hybrids. During the research years positive overdominance was determined in 17 out of 20 crossing combinations. In 2018 and 2019 all first-generation hybrids inherited total bushiness by positive overdominance. When hybridizing by maternal form of mediumearly, medium-ripening and medium-late varieties of soft winter wheat, the determined indicators of the degree of phenotypic dominance in 2018- 2020 indicate that the determination of total bushiness in 97.9% of hybrids occurred by positive overdominance – hp = 2.1-95.0. Intermediate inheritance was observed only in the hybrid «Antonivka/Vidrada» – 2020. According to the research data, it was established that the degree indicators of phenotypic dominance of total bushiness in hybrids depended on both crossbreeding components selection and the year conditions. Key words: parental forms, hybrids, phenotypic dominance degree, total bushiness, soft winter wheat.