Purpose. To analyze the divergence of early maturing source material of corn Zea mays L. in heterosis breeding for the genetic base formation at the State Institution the Institute of Grain Crops of the NAAS of Ukraine. Methods. Field (comprehensive assessment of morphobiological and economically valuable characteristics of the source material and maize hybrids) individual selection, cumulative and recurrent selection, backross and testcrosses bree­ding methods; laboratory; analysis and synthesis; statistical. Results. The results of research on the analysis of the divergence of early maturing corn source material in the conditions of the Steppe of Ukraine has become a developed harmonized working collection of corn breeding samples adapted to the stressful conditions of this region. The gradual cyclical improvement of the lines made it possible to form the core of the genetic diversity of FAO 150–290 early maturing specimens of the southern ecotype, which are competitive in heterosis breeding. The complexity of breeding for early maturity in the steppe conditions is due to the lack of material adapted to the stress factors of the South of Ukraine. The available early maturing lines of the world collection F2, F7, Ер1, Ма21, Ма23, Со125, Со255, См7, PLS61, S72, etc., were distinguished by high cold resistance, good starting plant development, intensive accumulation of dry matter during ripening, but not adapted to the deficiency of moisture in the soil and high summer temperatures. According to the results of the experiment, it was revealed that, in terms of breeding, lines of Lancaster plasma (DK427 and DK633) were the most plastic, due to which a number of new mid-early lines were obtained, for example DK2/427, DK267, DK266/417, DK633/266, DK296, etc., which were included in the registered hybrids. Formation of the genetic base of early maturing maize source material for heterosis breeding and systematization accor­ding to different breeding characteristics provided a balance of samples of alternative components, which will be further used to model heterosis hybrids in the early maturing group. Conclusions. The updated basic collection of lines is represented by the samples of plasma Iodent: DK744SVZM, DK216SVZM, DK4173SVZM, DK235zS, DK257zM, SV, DK365SVZM, DK777ZMSV, DK733-7zM,SV, DK315SVZM; Lancaster: DK296zS,VM, DK633/266zS,VM, DK2965ZSZM, DK2953 ZSZM, DK3023 ZSZM, DK236zS,ZM; Raid (SSS): DK232MV, DK2323MV, DK239MV; Mixed: DK253ZSZM, DK273MV, DK272zS, DK281SV, DK233zM,SV, DK959MV, DK9527 ZSZM, DK247MV, DK2442MV, which is the basis of the genetic diversity of early ripening corn samples included in the State register of plant varie­ties suitable for dissemination in Ukraine.

Мета. Установити успадкування елементів продуктивності головного колоса гібридами першого покоління пшениці м’якої озимої, отриманих від схрещування сортів, які є носіями пшенично-житніх транслокацій (ПЖТ) 1ВL/1RS і 1AL/1RS. Методи. Фенологічні, біометричні та статистичні. Результати. Відзначено диференціацію елементів структури врожаю між гібридами F1. У 2016 р. за результатами аналізу довжини головного колоса гібридів F1 наддомінування виявили у 26,7% із них, частково позитивне домінування – у 10,0%; за кількістю зерен: наддомінування – у 13,3%, частково позитивне домінування – у 10,0%; за масою зерен із головного колоса: наддомінування – у 16,7%, часткове позитивне домінування – у 3,3%. У 2017 р. за довжиною головного колоса наддомінування визначено в 36,7% гібридів першого покоління, часткове позитивне – у 10%; за кількістю зерен: наддомінування – у 46,7%, часткове позитивне домінування – у 6,7%; за масою зерен із головного колоса: наддомінування – у 40,0%, часткове позитивне домінування – у 10%. Селекційно найціннішою за поєднанням дов­жини головного колоса та маси зерен із нього є пряма комбінація схрещування ‘Колумбія’ / ‘Експромт’ (1AL.1RS / 1AL.1RS), у якої виявлено гетерозис у 2016 і 2017 рр.; за поєднанням кількості й маси зерен із головного колоса – ‘Світанок Миронівський’ / ‘Легенда Миронівська’ (1BL.1RS / 1BL.1RS). Поєднання двох транслокацій у пшеничному генотипі може виступати як допоміжний генетичний фон, який підвищує адаптивні властивості генотипу до стресових умов довкілля та забезпечує високий і сталий рівень зернової продуктивності. Висновки. Виявлено різний ступінь успадкування елементів зернової продукції в гібридів пшениці F1. Виділено гібридні комбінації F1, які забезпечили наддомінування та часткове позитивне домінування довжини, кількості та маси зерен головного колоса від схрещування сортів-носіїв ПЖТ. Селекційно найціннішими генотипами за поєднанням довжини головного колоса і маси зерен із нього є ‘Колумбія’ / ‘Експромт’ (1AL.1RS / 1AL.1RS), а кількості та маси зерен із головного колоса – ‘Світанок Миронівський’ / ‘Легенда Миронівська’ (1BL.1RS / 1BL.1RS).

Рurpose. To investigate inheritance of “plant height” trait in populations of the first (F1) and second (F2) generations of the soybean (Glucine max (L.) Merrill) and evaluate hybrid combinations in order to identify phenotypes with the highest level of heterosis for plant height. Methods. Laboratory test, mathematical and statistical analysis. Results. The inheritance of plant height in soybean was investigated. Hybrid combinations were assessed for the ability to select phenotypes with an optimal height. Different types of inheritance of this trait were found in populations of the second generation. The highest degree of heterosis for plant height was expressed by such soybean hybrids of the second generation as ‘АЕЕМ ’/‘Cherniatka’ (102.6%), next were ‘№ 427/‘Коrado’ (36,1%) and ‘Yelena’/‘Vizhion’ (32,0%). For the above trait, the ‘Legend’ variety in combinations with such varieties as ‘Staroukrainka’, ‘Korado’ and ‘Medeia’ expressed a heterosis amounting to 28.1%, 8.3%, 6.1% accordingly. Plant height was inherited mainly in terms of negative overdominance (34.2% combinations). There were 21.1% of combinations that had a negative semidominance. Conclusions. Among large majority of crossing combinations, forms were revealed that differed greatly for the plant height. The highest variability was observed in combinations such as ‘Legenda’/‘Korado’, ‘Ustia’/‘Vizjion’, ‘№894’/‘Vizjion’, ‘Ug-30’/‘Vizjion’, ‘Legenda’/‘Annushka’, ‘№441’/‘Gentleman’, ‘№441’/‘Vizjion’, ‘Yug-30’/‘Gentleman’, ‘Angelica’/‘Annushka’ and ‘Angelica’/‘Gentleman.

Purpose. Creation of experimental sugar beet hybrid combinations of high sugar yield values and defining gene­tic determination of their heterotic effect. Methods. Diallel crossing and topcrossing, genetic analysis of quantitative traits. Results. The authors have studied the frequency of occurrence of sugar beet heterotic hybrid combinations for «sugar yield» trait created on the basis of two pollinator lines to be genetically valuable for productivity elements, CMS lines and single-cross sterile hybrids with the use of diallel and topcrossing system of controlled hybridization. The share of parental components’ effect and their interaction in CMS hybrids variability for productivity was determined. Expediency of heterotic forecasting based on high combining ability lines was substabtiated. Promising high-yielding sugar beet combinations were selected that exceeded the group standard by 4.1–16.3%. Conclusions. The theory of genetic balance by M. V. Turbin was confirmed. Such hybrids as [CMS 5OT 4]MGP 1 (116.3%), [CMS 1OT 2]MGP 1 (112.5%) and [CMS 3OT 5]MGP 1 (113.2%) were recognized as the best for their productivity, MGP 1 and MGP 2 lines – as the best for their combining ability.

A stabilizing (directed) selection has created a donor of short stem for winter rye (Secale cereale L.), plant height of which ranged from 50 to 60 cm. The plant height kept symmetry of its distribution curve and the frequency accumulation in central classes (positive excess). For the first time a symbolic designation to new short-stem related Hl-2Hl-2 allele and the donor name (Gnome 2) were proposed. 28 years of stabilizing selection showed that 57% of overall genetic variability of plant height resulted from adaptive genes available for directed selection by phenotype, and 43% from dominant and epistatic factors that predetermines the expression heterosis effect. Gnome 2 donor proved to have genetic additive correlation between the pants height and number of flows per ear, ear length, weight of seeds per plant , 100 seeds weight per plant; to have reverse correlation with ear density seeds weight per ear. The height of original parent components have displayed direct additive correlation with number of flowers per ear and reverse with the ear density. The additive correlation component directly exposes «genuine» impact of parental plants on the expression of the characteristics indicated among the offspring Productive bushing of parental plants, seed weight per plant directly, and seed size (100 seeds weight) indirectly, respectively, influence the height of offspring pants. The reverse additive correlation between the parents height and 100 seeds weight in the offspring is caused by pleiotropic effect of the genes impact thus enabling to combine the desirable characteristics in one genotype. Productive bushing is by 54% due to the impact of general genetic factors among the above, in particular, 30% due to that additive, 24 due to non-additive factors. The concept of genetic improvements for productive bushing of the Gnome 2 rye implies utilization of additive effect through the directed selection, as well as application of breeding techniques for controlling the effect of heterosis caused by the genes of dominant and epistatic impact. The selection paradigm requires simultaneous genotypes selection with immediate examination of the selection results by offspring while in parallel to develop inbred lines, combining these afterwards evaluating general and specific combining ability by productive bushing. It is also to be noted that the productive bushing essentially depends on the environmental conditions, which significantly corrects the implementation of productivity potent, thereby the issue of agronomical conditions aimed at extending the expression of characteristic in question remains.

The article offers short characteristic of Fj hybrid combinations and reveals type of inheritance by the folwiing characteristics: plant height, height of lower bean insertion, quantity of seeds per plant, quantity of seeds per plant, beans per plant, nodes and branches per plant, as well as determines proportion of dominations displaying high heterosis effect. Two superior hybrid populations, namely Amethyst/Miao-ian-Dou and Amethyst/Krasa Podillia, have been selected and are being used to scan for transgressive forms.

Genetic and statistical analyzes of ten quantitative characteristics inheritance of reciprocal populations F2 of three-hybrid crossing by plant height, leaf blade electroidy and absence of glaucosity on the plants of Winter Rye in three breeding institutions – Nosivskiy Variety Testing Station (VTS), Verhnianskiy VTS and Volynskiy Institute APV. Major portion of phenotype variation has been determined by environmental factors. Genotype variability of those characteristics is predetermined by effects of domination and epitasis, so the breeding aimed at acquirement of heterosis effect when ZKZ (ЗКЗ) and SKZ (СКЗ) are applied is expected to be promising.

Three synthetics of Winter Rye were being observed for the quantity of seminal roots (QSR) to study their inheritance. High inheritance coefficients in a restricted sense were established. Genetic improvement of the Rye may be a result of direct breeding and of using heterosis effect. QSR expressed essentially negative genetic correlation with plant height, positive with grain size, productive bushiness and weight of grain in the ear of successors, as well as with grain yield per unit of the area. Genetic correlation coefficients shall be used in the applied breeding.

Advantages of heterotic hybrids of the winter rape in the competitive and in the production testing proven. While certain advantages in the productivity of cultivar of the Czech selection of Odila above the domestic cultivar of Dangal got in the competitive testing in the production testing confirmed. It is established that the greatest productivity in the production testing was had hybrids Vsesvit F1t Zapalnyj Fb G-3 Fi and G-4 Fi, which are characterized the stable and yearly high productivity and combine the productivity with adaptability to the environmental conditions of area of Forest- steppe of Ukraine.

The use of regression analysis for estimation of inbred lines is a breeding - oriented method, as it indicates scientifically grounded stages of the further breeding studying of these lines and a strategy of their use. Admissible levels of inbred depression of agriculturally valuable characters are limited in lines of the Verkhnyachka and Lgov geneplasms by two - three generations of self - pollinations, which testifies to the necessity "to keep" the characters of sufficient basis. Linearity of changes of values of the characters with the advancing of inbreeding shows the absence of epistasis or the weakness of their effects which makes suitable the use of an additive-dominant model for determining breeding-genetical value of inbred lines with the aim of their purposeful hybridization for obtaining genetically determined heterosis in F1.