Manifestation of the heterosis effect of valuable economic traits in sunflower hybrids resistant to mildew

Abstract

Goal. To establish the manifestation of the effect of heterosis in the first-generation sunflower hybrids in terms of productivity and plant height, created based on new lines resistant to false mildew in the system of simple diallel crossings in 3 groups, in particular: simple restored hybrids, simple sterile and simple artificially created according to the scheme RfRf/RfRf. Methods. Statistical, which were based on the analysis of the results of research in the system of direct diallel crosses of lines, to determine the stimulating effect of heterozygosity in first-generation sunflower hybrids resistant to mildew according to 2 useful traits: plant height and productivity; laboratory, which included the analysis of damage by the causative agent of mildew at the first stages of ontogenesis. Field research on the experimental fields of the Institute of Plant growing of NAAS in the conditions of the Eastern part of the Forest-Steppe of Ukraine with the selection of hybrid combinations resistant to mildew was carried out according to generally accepted methods. Results. The optimal height of plants in new hybrid combinations of 3 types was established. Exclusion of the subjective factor, which was damaged by false mildew, made it possible to detect the manifestation of the effect of true and competitive heterosis on the main economic characteristics: plant height and productivity in hybrids created based on new sunflower lines with a different set of dominant genetic determinants, such as restoration of pollen fertility, high content of oleic acid, resistance against herbicides of the sulfonylurea group, the causative agent of NBR and lupus. Promising hybrid combinations for the implementation of the selection program for the creation of highly productive hybrids adaptable to environmental conditions were noted. Conclusions. The results of studies on the productivity of the sunflower plant indicated the individual response of hybrids to the conditions of the growing year, which depended on the level of adaptability of the genetic material, and were a subject for further research in different environmental conditions. In the 3 studied groups of hybrids, the manifestation of the effect of true heterosis in the height of plants was found in the range of 5.00–41.50% depending on the conditions of the year. The manifestation of an insignificant effect of competitive heterosis on this feature compared to the accepted standard was proved. A high level of manifestation of the effect of true and competitive heterosis on plant productivity was established, which fully corresponded to the tasks of sunflower selection in Ukraine.