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.

Methodology for detecting correspondence of soft wheat to the criteria of distinctness, uniformity and stability based on researching peculiarities of morphological characteristics expression, has been scrutinized. It is established that, in the complex of many of those characteristics characterizing variety phenotype, for its identification only those characteristics are used that are exposed to lesser degree to the influence of environmental conditions.

The article researched genetic potential, morpho-biological characteristics and features of new varieties of winter wheat varieties of semi-dwarf and short-stem types. It was established that new generation of such varieties displayed improved architectonic of plants, as well as a complex of morphological and economical value chararacteristics and features, combined high genetic potential of productivity with good adopting features, and short stem with high resistance to drowning, and generated higher crop capacity compared to conventional mid-ripening varieties.

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.

It is concluded by investigations that wheat crossing of various development types between themselves cause increase of formbuilding process in hybrid progeny, promoting the selection of practically valuable recombinats. The genotypes which present the practical valuable by complex of adaptive traits and properties have been selected by phenotype stability in the breeding process. The new bread winter wheat variety Pamyati Remesla developed with participation of spring wheat variety Hja 22139 (Finland) has been proposed for including it into the Register of Plant varieties of Ukraine adapted for use in Steppe, Forest- Steppe and Woodland of Ukraine since 2010.

Results of studying of influence of sowing terms on productivity and indices of quality of grain of winter bread wheat variety-innovations of V.M. Remeslo Myronivka Institute of Wheat of NAAS of Ukraine in the conditions of Right-bank Forest-steppe are shown. Negative correlation of productivity of varieties on average temperature of air during the sowing period is shown.

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.

As a result of the lead long-term selection works wint involving a World' s collection and intertype and intertype hybridization with purposeful selection on economic-biological attributes highly productive • grades of a winter wheat, with stability to various kinds of illnesses and high technological qualities of grain have been allocated. The adapted grades of a winter wheat for a various environment of various zones of the countries of the Central Asia that allows to realize potential opportunities of grades in different environments of cultivation and by that to prevent losses of a crop from biotic and abiotic stresses that allows to stabilize productivity and adaptability of culture in a zon winter husbandry are created. The long-term field experiences lead by us and laboratory analyses on a level of productivity, qualities of grain and stability to stresses allows to conclude, that alongside with a genotype, stabilityenvironmental conditions render strong and significant influence on all complex of selection attributes.

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.

The study of impact of complex application of biological compositions based on fixing nitrogen by microorganisms and plant lectin and nitric fertilizers on productivity and quality of grain of winter wheat on the dark-grey soil in the field terms was conducted. It is shown, that presowing treatment of seed by biological compositions stimulated forming of greater productivity with the best quality.