Purpose. To reveal the nature of the inheritance of apricot color of the ray flowers of the sunflower and the type of interaction of genes causing different colors. Methods. Field experiment, genetic analysis. The statistical validity of the results was evaluated using Pearson’s criterion. Results. We conducted crosses of the ‘KG13’ line as the source of the sign of apricot color with sunflower lines that had yellow, orange and lemon colors of the ray flowers. In the first generation, from crossing the ‘KG13’ line with five lines, which had a yellow color, only a yellow color of ray flowers was observed. In the second generation, a 3 : 1 split was observed: three-quarters with yellow flowers and one with apricot flowers. Line ‘KG13’ was crossed with three lines (‘HA298’, ‘SL2966’, ‘LD72/3’), which had an orange color of flowers. In the first generation, orange flowers were observed; in the second gene­ration, splitting was recorded: three-quarters of offsprings with orange-colored flowers and one-quarter with apricot flowers. The line ‘KG13’ was crossed with ‘KG107’ and ‘ZL678’, which had lemon-colored flowers. The resulting plants of the first generation had a yellow coloration of ray flowers. In the second generation, five classes of plants by coloration of ray flowers were obtained: yellow, orange, apricot, lemon, lemon-apricot in the ratio 6 : 4 : 3 : 2 : 1. According to these data, the genes of lemon and apricot color have a complementary effect, the homozygous state of orange allele is epistatic to the recessive homozygote of the lemon-colored gene. The ‘KG108’ line with a combination of genes responsible for apricot and light yellow color has its own light apricot color and in crossings with a yellow colored line in the second generation gives splitting in the ratio 9 : 3 : 3 : 1. Conclusions. It was revealed that the apricot color of the ray flowers of the sunflower line ‘KG13’ is due to the homozygous state of the allele of the same gene whose second allele causes an orange color in the lines ‘NA298’, ‘SL2966’ and ‘LD72/3’. The complementary action of alleles responsible for apricot and lemon, as well as apricot and light yellow coloration of ray flowers was determined. A case of epistasis of homozygotes along the allele controlling the orange color over the recessive homozygote of the gene, which is controlled by the lemon color in the crossing combination ‘ZL678’ / ‘KG13’, was revealed.

Purpose. To determine the level of productivity of sunflower hybrids, their stability and plasticity for cultivation in the Left Bank Forest-Steppe of Ukraine. Methods. The field experiment was performed in the conditions of the Left-Bank Forest-Steppe of Ukraine in 2016–2018. The peculiarities of plant growth and development, formation of yield of hybrids ‘Ukrainskyi F1’ (k), ‘P64LL125’, ‘P63LE10’, ‘P64F50’, ‘P64F66’, ‘P63LL06’, ‘NK Konti’ (k), ‘NK Brio’, ‘P64LE99’, ‘Laskala’, ‘Kupava’. Yield plasticity was calculated and analyzed by the Ebergard – Russell method. Results. Over the years of research, the average yield of sunflower hybrids in the Left-Bank Forest-Steppe of Ukraine varied from 2.71 to 4.04 t/ha. The lowest yield was shown by the ‘Ukrainskyi F1’ hybrid – 2.42–3.05 t/ha, the highest ‘Laskala’ – 3.79–4.26 t/ha. It was determined that in the conditions of the Left-Bank Forest-Steppe, there is no absolute predominance of medium-ripe hybrids in terms of yield. Conclusions. According to the results of the analysis of yield plasticity of sunflower hybrids, it was determined that the group of samples with high yield plasticity includes ‘Ukrainskyi F1’, ‘P64F50’, ‘P64F66’, ‘NK Konti’, ‘NK Brio’, ‘P64LE99’, ‘Lascala’ and ‘Kupava’. They respond to the improvement of the level of agricultural technology and provide the maximum yield only under the conditions of optimal factors. Hybrids ‘P64LL125’, ‘P63LE10’ and ‘P63LL06’ are more stable in response to changes in growing conditions without reductions in yield. As for the shares of the influence of the studied factors, the yield of the hybrid ‘Ukrainskyi F1’ was most influenced by the conditions of the year, ‘NK Brio’ – the sowing rate. For the ‘NK Ferti’ hybrid, the conditions of the year and the sowing rate are equally important.

Purpose. To assess introduced samples of drought-resistant species of perennial grasses, select a promising parent material and create on its base high-yielding varie­ ies with economic characters. Methods. Field experiment, laboratory testing. Results. The results of studies on introduction and breeding were given aimed to improve drought tolerance of non-traditional perennial grasses under the conditions of the Right-Bank Forest-Steppe zone of Ukraine. Based on the selected parent material, varieties were created by the use of hybridization and ecotype breeding methods and then entered into the State Register of plant varieties suitable for dissemination in Ukraine, among them: intermediate wheatgrass (Elytrigia intermedia (Host) Nevski) – ‘Hors’, crested wheatgrass (Agropyron cristatum (L.) Gaertn.) – ‘Petrivskyi’; meadow brome (Bromus riparia Rehm.) – ‘Boian’; slender wheatgrass (Roegneria trachycaulon (Link) Nevski) – ‘Co­umb’. As compared with conventional, relatively drought-tolerant species of smooth brome (Bromopsis inermis (Leyss.) Holub) – ‘Mars’, increment of dry matter content of these species in the extreme drought conditions of 2011 was increased by 1,52–3,73 t/ha. Under more sufficient moistening conditions of 2012, slender wheatgrass ‘Columb’ was at the level of the сheck variety in terms of this indicator. Other varieties exceeded it by 1.44–3.22 t/ha. The data was given including seed productivity and sowing quality indicators, after-ripening duration and economic fitness of seeds. Conclusions. The use of the recommended varieties of drought-resistant species of perennial grasses as part of grass mixtures will increase significantly the productivity of grasslands and pastures in the current context of climate change.

Purpose. To determine the effect of the basic organo-mineral fertilizer on the formation and stability of grain quality of winter wheat varieties in multiple crop rotation after black fallow as a predecessor. Methods. Field experiments were based on a multifactorial scheme using split-plot method with due regard to all requirements of the field experiment procedure, analysis of variance was used for statistical processing of the obtained results. Results. Investigation data was given concerning determination of grain quality indices in winter wheat varieties of diffe­rent ecotypes after black fallow as a predecessor depending on organo-mineral fertilizer application in the Left-Bank Forest-Steppe zone of Ukraine. In average for the period of investigation (2011–2015), the highest protein content in winter wheat grains was formed in no treatment variant [in such varieties as ‘Doridna’ (14.1%), ‘Dykanka’ (14.3%) and ‘Levada’ (14.2%)] and in case of organo-mineral fertilizer application [in the varieties ‘Hordovyta’ (14.0%), ‘Kalyta’ (14.0%), ‘Dykanka’ (14.7%) and ‘Levada’ (14.6%)]. The highest content of crude gluten in grains, without regard for the variant of the experiment, was found in the following varieties as ‘Dykanka’ (24.9–25.1%) and ‘Levada’ (23.7–25.4%). Conclusions. It was established that the content of protein and crude gluten in grains as well as the falling number of winter wheat was highly dependent on such factors as the variety and the year of cultivation as compared to the fertilizer background. The following varieties as ‘Hordovyta’, ‘Mulan’, Dykanka’ and ‘Levada’ were very sensitive to the application of organo-mineral fertilizer for the protein content, while ‘Hordovyta’ (2.4%), ‘Levada’ (1.7%), ‘Borvii’ (1.2%) and ‘Mulan’ (1.1%) – for the crude gluten content.

Purpose. To estimate genetic resources collection of soft winter wheat plants (new collection accessions) of Ustymivka Experimental Station for Plant Production and select initial material for breeding of adaptive, productive and qualitative soft winter wheat varieties. Methods. Field experiment, laboratory testing. Results. The authors pre- sented results of study of over 1000 samples of gene pool of soft winter wheat from 25 countries during 2001–2005 in Ustymivka Experimental Station for Plant Production of Plant Production Institute nd. a. V. Ya. Yuriev, NAAS of Ukraine for a complex of economic traits. More than 400 new sources with high adaptive properties were selected that combine traits of high productivity and high quality of grain, early ripening, resistance to biotic and abiotic fac- tors (the assessment of samples for 16 valuable traits is given). The selected material comes from various agro-cli- matic zones, including zones of unsustainable agriculture. Conclusions. Recommended sources of traits that have breeding value will allow to enrich high-quality assortment of wheat and considerably accelerate breeding process du- ring development of new soft winter wheat varieties.