Inheritance of kernel number per spike in F1 of spring barley obtained from crossings of cultivars of different origin, purpose of use and botanical varieties

Purpose. To reveal the peculiarities of inheritance of kernel number per spike in crosses of spring barley cultivars of different origin, purpose of use and botanical varieties, as well as to distinguish effective genetic sources for impro­ving the trait. Methods. The study was carried out at the M. Remeslo Myronivka Institute of Wheat of National Academy of Agrarian Sciences of Ukraine in 2019 and 2020. In F1 of spring barley in two diallel crossing schemes the degree of phenotypic dominance, parameters of genetic variation, and combining ability for kernel number per spike were determined. Results. According to the indicator of the degree of phenotypic dominance, all possible types of inheritance of kernel number per spike were identified. In a number of crossing compositions, a change in the type of inheritance depending on the conditions of the year was revealed. Most combinations with overdominance in both years were noted in crossings of the covered awned cultivar ‘Avgur’, as well as the covered awnless cultivar ‘Kozyr’. According to the parameters of genetic variation in crosses of malting varieties (covered awned), correspondence of the additive-dominant model, overdominance and dominance in loci, as well as unidirectional dominance to increasing of the trait caused by dominant effects were revealed. When crossing cultivars of different varieties, a change in gene action in different years was found. In particular, additive-dominant system changed to complementary epistasis, incomplete dominance to overdominance, unidirectional dominance to increa­sing of the trait to multidirectional dominance. The genetic sources of increased general combining ability were identified, as follows: covered awned malting cultivars ‘Quench’ and ‘Avgur’, the naked awned cultivar ‘CDC Rattan’, as well as the covered awnless cultivar ‘Kozyr’. Based on the constants of specific combining ability, the most promising crossing combinations for further breeding efforts were determined. Conclusions. The identified peculiarities of the inheritance of kernel number per spike make it possible to optimally combine parental components of crossings and carry out directional selection to increase the trait when developing spring barley cultivars for different use and different botanical varieties