Trotsenko V. The theoretical and practical bases of sunflower breeding for adaptability in the North-Eastern Forest-Steppe of Ukraine

The theoretical generalization and the new solution of scientific problem concerning the substantiation and realization of breeding programs for creation of sunflower initial material and its varieties oriented on cultivation in certain soil-climatic conditions have been presented. For the first time the methods of creation of sunflower original material adapted to the specific conditions of the North-Eastern forest-steppe and Polissya of Ukraine have been developed, tested and put into production in the form of new high-yield varieties. Some methods for estimation of breeding material and initial seed-production have been improved. There have been established some differences in the list and the parameters of the important breeding features the best values of which in more southern conditions are maintained by environmental influence. It has been revealed that earliness is the important characteristic but not the only one adaptive parameter of genotypes to the conditions of the region. Tolerance parameters require the selective control because of changing the crop density, soil acidity and its temperature. Methods of control of the basic schemes dealing with the formation of plant productivity have been elaborated and introduced into breeding practice. The introduction of such methods ensures the essential decrease of the parameters concerning the duration of vegetative period under the preservation of productivity of the main parameters. The peculiarities in the mechanisms of yield formation in crops with different plant density have been determined. It has been determined that the creation of varieties have to occur taking into account the predicted level and the range of variability index of the pre-harvest density. Under research conditions the highest rate of variation belongs to the index of period length "end of vegetation-complete (technological) ripening". The efficiency in use of this parameter as a separate breeding trait has been experimentally proved. It has been found out that one of the mechanisms of matrykal-seed formation is the difference in number between the formed embryo cells and the level of its structure depending on the location of seed in inflorescence. The extension of the adaptive potential of varieties to the specific conditions of separate vegetation periods characterized by different mechanisms of yield formation can be achieved by optimization of first fraction seeds. It has been experimentally proved that steady preservation of early-ripening parameters is guaranteed only in case of first fraction seed use. The distinction between the hereditary traits of different seed fractions decreases in varieties with low-intensity selection for early-ripening. The following varieties of oil sunflower have been created and entered in the National Register: Postolyanskyy, Sumchanyn, ChaS, Hutoryanyn; confectionery sunflower: Onyx. Varieties Fahrenheit and Siajvo are being tested.