METHODOLOGICAL IMPROVEMENT OF THE APPLICATION OF APOMIXIS IN TOBACCO BREEDING FOR CONFIRMATION OF HETEROSIS

Abstract

The source material for the research was collection samples bred by breeders of the station and introduced from European countries, registered in the National Genetic Fund of Ukraine. Hybridization was performed according to the diallel scheme and F1 seeds from 36 hybrid combinations were obtained. The best hybrids with a high effect of heterosis are transferred to the apomictic basis in order to consolidate heterosis. The obtained apomicts were sown and 7 with the best indicators were selected according to the set of traits and checked for the presence of apomictic properties for sowing in the future to obtain hypomites-apomict with high productivity. The best hybrid combinations were selected by quantitative characteristics, which showed a positive dominance and are of practical interest for the consolidation of heterosis through apomixis and further testing in a competitive nursery. As a result of a detailed analysis of the specific splitting of forms in A1, it should be noted that each hybrid combination has its own specific splitting and there is no pattern of manifestation, as observed in the second hybrid generation. Criteria for selection of possible apomites according to the ability to form plants in A1 with maternal traits in about 25% of plants and selection of seeds for further sowing only after castration of flowers and removal to the isolator. In the second generation A2 there is a high level of constancy, which allows the selection of plants without castration, but the selection under the insulator. The main marker for the identification of genotypes with elements of apomixis are morphological features of the maternal type, which requires planting next to hybrid seeds of the first generation. In the breeding practice of tobacco to improve the source material and consolidate heterosis through apomixis should use an improved method of evaluation, which consists in collecting seeds for further study of A1 through castration of flowers and growing seeds under the insulator, selection of A1 plants by maternal type, which requires placement next to the plant F1 and formation of seed stock for re-seeding. Keywords: tobacco, apomixis, ecological stability and plasticity, heterosis, consolidation of heterosis effect