Purpose. To establish correlation dependence of influence of such factors as seeding rate, sowing time and seeding methods on yield indicators, as well as individual response of winter wheat varieties to them in case of the ecological system of seed production, that would allow to form elements of intensive varietal technology and obtain the genetically determined productivity potential of the variety in the future. Methods. Weight measuring was used to determine seed yield; the reliability of the experiment results was identified by statistical evaluation, analysis of variance and regression procedure. Results. During the period of investigation, the weather conditions differed significantly both for the temperature regime and the amount of precipitation, but the stability of grain and seed yield over years was the main requirement to varieties, that allowed to study the intergenotypic correlation relationships of crop yield indices and the dynamics of their changes under the effect of ecological factors. In the course of investigation, winter wheat yield indices were fixed annually from 684 plots, which were grouped and analyzed for factors of influence in order to ensure the complete certainty. Conclusions. Variants of investigation were defined for the certified seed yield and environmental factors (sowing time and seeding method, seeding rate), that had strong positive correlation relationships. Seeding rate and seeding method had the greatest impact on 1000 kernel weight. For tille­ring coefficient, varieties depending on the variant of the investigation had a negative close correlation relationship, which was greatly affected by seeding rate. For correlation relationships, winter wheat varieties ‘Bohdana’ and ‘Slavna’ appeared to be the most stable, ‘Chorniava’ and ‘Astarta’ were the most plastic.

Purpose. To define the level of impact of such factors as rate, time and methods of sowing on seed productivity and certified seeds, and the individual response of winter wheat varieties to these factors if used the ecological system of seed farming, that would allow to form and obtain genetically determined potential of variety productivity. Methods. Weight measurement for determining seed yield; statistical, variance and regression analysis for identifying the reliabi­lity of the experiment results. Results. During the research period, weather conditions were greatly differed both by temperature regime and precipitation, but stability of grain and seeds yield on an annual basis was the main requirement to varieties. During the study of «grain productivity» value and quantitative indices of winter wheat yield structure, the results from 684 plots were obtained which were grouped and analyzed for impact factors for complete certainty, and NIR0,05 was calculated. Conclusions. Thus, in case of shifting sowing time from optimum to later period, efficiency of water use by plants was decreasing to a greater extent during years with insufficient precipitation. The shift of sowing time to later period providing optimal seeding rate and row seeding method did not reduce yield. The yield of winter wheat varieties to be studied when sowing in usual manner with seeding rate of 5,5 million seeds/ha in the period from September 15 and October 5 was the highest. Varieties ‘Slavna’ and ‘Chorniava’ provided the highest grain productivity for seeding rate of 5,5 million seeds/ha and using row seeding method, with slight impact of sowing time factor. Grain yield of studied varieties showed negative response during the experiment when seeding rate decreased up to 2,5–3,0 million seeds/ha. ‘Astarta’ varie­ty provided the highest productivity for certified seeds yield as compared to the control (from 1,59 to 3,38 t/ha). The variant of the experiment when sowing on October, 5 in usual manner with seeding rate of 5,5 million seeds/ha showed the highest productivity of 7,02 t/ha (+3,38 t/ha, or +92,9%). Shifting of sowing time for October, 5 resulted in a significant decrease in yields of certified seeds as compared to sowing time on September 15 and 25. Seed yield of studied varieties when sowing on October, 5 was higher than in case of sowing on September, 25. The highest percentage of certified seeds output in the studied varieties was observed for a seeding rate of 2,5–3,0 million seeds/ha. For seeding rate of 5,5 million seeds/ha for varieties with seeding time between September 15 and 25, the difference in grain yield was negligible. The winter wheat variety ‘Astarta’ provided the highest yield of seeds during the research years – 9,36 t/ha, the standard variety ‘Bogdan’ – the lowest one in the best variant of 5,55 t/ha.

Influence of varietal characteristics and growth factors on the quality of Natsional’na and Polis’ka 90 winter wheat varieties was studded. Grain of Polis’ka 90 variety was distinguished by considerable variability of grades, however, the grain of Natsional’na variety was exposed to greater number of growth factors. Grain unit index influenced the grain quality grade of Natsional’na 90 determination, gluten quality and protein and fiber content indices influenced that of Polis’ka 90. It was established that the grain of Polis’ka variety in most of the cases had higher grades of quality than Natsional’na variety. The highest grades of quality were registered for the seed harvested after perennial grasses, namely 2d and 3d grades of Natsional’na variety and the 1t and the 2d for Polis’ka 90 variety. Greater grades of quality were registered for the seed grown according to intensive and ecological farming systems (generally, grades 1 to 3), while the lower grades were inherent to biological system (generally, grades 3 to 5).

Such varieties of winter wheat as Ovidium, Kokhana, Blago, Maria, Andromeda possess high adaptive potential, there are possible to use on irrigated and unirrigated lands. New genotypes are able to guarantee yield on level accordingly 9,0-9,5 and 5,5-6,0 t/ha. They are form the grain of strong and valuable wh eats.

When studying period of maturation after harvest, varietal specificity of level of winter wheat seed maturation process reaction on hydrothermical factors has been revealed. This trait should been taken into consideration when deciding practical problems in respect to rational variety-regionizing as well as to development of seed technology based on biological peculiarities.

Giving regard to the main elements of Winter Wheat varieties assessment when selecting frost resistant plants and taking into account genetic potential of the parents, date of hybrids sowing and their assessment by the speed of spring vegetation, it is possible in the sense of successful breeding to derive the most steady genotypes by the specified characteristics starting from F1. hybrids.

The results of research of the drought tolerance of winter wheat varieties (Triticum aestivum L.), which are suitable for the dissemination in Ukraine are presented. Differentiation of varieties according this trait is made. Groups of varieties were classified. Ways of improvement of the assessment are suggested.

Quality of Spring Soft Wheat varieties listed in the State Register of Varieties of Ukraine for 2008, according to the grain quality indices (protein content, flour vigor, bread volume). Over 86% of Winter Wheat varieties bred by Ukrainian breeders are classified according to their quality to the strong and valuable, in contrast to 14 % of foreign varieties. This is the evidence of the Ukrainian breeding varieties ability to compete.

Purpose. Provide bioinformatic analysis and comparison of target regions of the acetolactate synthase (als) gene in several members of the Poaceae family and, on the basis of the obtained data, explore the possibility of creating a unified genetic construct for als gene editing using the CRISPR-Cas9 system. Methods. The als gene sequences of various members of the Poaceae family were obtained from the NCBI: Nucleotide database. For comparison, a fragment of the imi-2 gene of wheat of the soft line ‘TealIMI11A’ was used in two regions of the 367–390 and 1729–1749 nucleotide sequences. The Sequence Viewer 3.37.0 tool was used to assess the presence of nucleotide substitutions in the working sequence of the imi-2 gene. The dendrogram was built using the “Blast Tree” tool from the NCBI: Blast: Nucleotide resource. Results. A comparative analysis of the nucleotide sequences of seven different species was carried out: soft wheat (Triticum aestivum L.), common wild oat (Avena fatua L.), barley (Hordeum vulgare L.), Asian rice (Oryza sativa L.), maize (Zea mays L.), aleppo grass (Sorghum halepense Pers.) and Tausch’s goatgrass (Aegilops tauschii Coss.). The dendrogram is based on the gene sequence als, showed that all studied genotypes can be divided into two blocks: the first block included maize and aleppo grass, and the second block, a separate branch includes Asian rice and common wild oat, barley, soft wheat and Tausch’s goatgrass. 367–390 nucleotide sequences of soft wheat showed the highest 100% homology to Asian rice, Tausch’s goatgrass and common wild oat. The lowest homo­logy was for maize and aleppo grass at 83.3%. Evaluation of the nucleotide sequence 1729–1749 showed no complete homology at the 100% level. It was the highest for barley and Tausch’s goatgrass – 95.2%, and the lowest for rice, maize and aleppo grass – 80.9% each. Conclusions. The analysis confirms a significant degree of homology of the als gene sequence for various species of the Poaceae family, which allows us to create a universal genetic vector. However, taking into account the high degree of sequence homology for species such as soft wheat, Tausch’s goatgrass, barley, Asian rice and common wild oat, it can be assumed that the corresponding genetic vector can be used with the greatest efficiency to alter the als gene of these genotypes.

Purpose. To determine the effectiveness of using contrasting sowing dates after different predecessors to assess the genotypes of bread winter wheat in terms of yield and stability. Methods. Field, laboratory, mathematical statistics. Results. A different, but reliable level of influence on the yield of bread winter wheat genotypes of such factors as conditions of the year of cultivation (66.2%), predecessors (12.5%), sowing date (6.1%) and genotype (1.7%) was revealed. Significant differences were noted in the response of the studied genotypes to the sowing date after different predecessors. Relatively less influence of the predecessors on the yield of the varieties ‘Estafeta Myronivska’ and ‘Vezha Myronivska’ was revealed, more – for the varieties ‘MIP Darunok’, ‘MIP Kniazhna’ and ‘MIP Vyshyvanka’. The sowing dates had less influence on the yield of the varieties ‘MIP Fortuna’, ‘MIP Vyshyvanka’ and ‘Trudivnytsia Myronivska’. A general tendency for decrease in the average annual yield was established in the experiment with a shift in the sowing dates from September 26 to October 16. However, for the number of genotypes after certain predecessors, the optimal sowing date was the 5th of October: after the predecessor, green-manure fallow – for varieties ‘Trudivnytsia myronivska’, ‘MIP Assol’ and ‘MIP Dniprianka’, after mustard – ‘Vezha Myronivska’, after sunflower – ‘MIP Fortuna’, after corn – ‘MIP Fortuna’ and ‘Podolianka’. In terms of sowing dates, the least variation in yield was found after the predecessors green manure, mustard and corn varieties ‘MIP Vyshyvanka’, ‘Balada Myronivska’, ‘MIP Kniazhna’, ‘Estafeta Myronivska’. Using the GGE biplot, it was found that close to the ‘ideal environment’ for the realization of the yield level of most genotypes was the second sowing date after greenmanure fallow predecessor. For different sowing dates and predecessors, on average for three years, the optimal combination of the level of yield and stability was noted for the varieties ‘Trudivnytsia Myronivska’, ‘MIP Vidznaka’, ‘MIP Assol’, ‘Estafeta Myronivska’, ‘MIP Valensiia’. Conclusions. Thus, the use of different so wing dates after various predecessors is an effective approach to organization of genotype-environmental tests. It makes it possible to identify the genotypes which are specifically adapted to certain conditions (predecessors and sowing dates) and genotypes with a relatively high level of stability when sowing after various predecessors and on different dates. This approach can be used both at the final stage of breeding to differentiate breeding lines for yield and stability, and in the development of basic elements of technology for growing newly created varieties.