ФОРМУВАННЯ ДОВЖИНИ ОСНОВНОГО КОЛОСУ ГІБРИДАМИ ПЕРШОГО ПОКОЛІННЯ ПШЕНИЦІ М’ЯКОЇ ОЗИМОЇ
The aim of research is to study the inheritance of the main ear length of soft winter wheat by hybrids of the first filial obtained by crossing cultivars that are carriers of wheat-rye translocations. The research on F <sub>1</sub> was carried out in 2013-2014 on experimental field of Sumy National Agrarian University, part of the north-eastern Forest Steppe of Ukraine. The climate of the area is continental. The average day and night (average annual) temperature in the growing 2013/2014 year was 9,5 ºC that is 2,1 ºC higher the long-term rate (7,4 ºC). The absolute maximum of the temperature (34 ºC above zero) marked during the second decade of August, the minimum of temperature (26 ºC below zero) during the third decade of January. The amount of rainfall was 552,6 mm, that is 40,4 mm less of many years norm (593mm). 30 hybrid combinations, created as a result of complete circuit diallel crossing scheme (6x6) of soft winter wheat have been taken as the material for research. The wheat cultivars of different genetic origin (Myronivs’ka rann’ostygla, Epoha odes’ka, Rozkishna) and cultivars - carriers of wheat-rye translocation (1AL/1RS - Smuglyanka, 1BL/1RS - Kryzhynka and Remeslivna) have been used as crossing components. Hybrid seeds were sown by hand, in a 3-fold repetition according to the scheme: the maternal parent, hybrid, staminate parent. Phenological observations were carried out during the vegetation, at their complete ripeness - structural analysis of sheaves. Based on the data of obtained results the heterosis level and phenotypic dominance degree were determined in the first generation hybrids. A significant differentiation between first-generation hybrid according to the length of main ear was determined during the analysis. The manifestation of true heterosis (0,30-16,30 %) and overdominance were observed in 17 % of hybrid combinations. In most cases, heterosis in accordance with the main ear length occurred in 3 combinations (K.27 - Smuglyanka / Remeslivna and reciprocal - K.11 and K.26 - Kryzhynka / Smuglyanka), with two translocations. The combination K.15 (Kryzhynka / Rozkishna) where one of the parent forms is a sort-carrier of 1BL/1RS translocation showed heterosis effect. The combination K.5 (Myronivs''ka rann''ostygla / Rozkishna) where parents do not contain genotype translocations had the highest heterosis effect (16,30 %). However, negative heterosis (-15,97 %) was observed in inverse combination (K.18) According to the length of the main ear with a negative heterosis effect (from -0,65 to -23,39 %) of the studied combinations 83 % were shown up, 5 of them were without translocations (K.4, K.9, K.10, K.24, K.25), 11 were where one of the parent forms contains 1BL/1RS translocation. The negative heterosis effect was observed in reciprocal combinations where both parent forms were carriers of 1BL/1RS translocation (K.12 - Kryzhynka / Remeslivna and K.16 - Remeslivna / Kryzhynka). 6 combinations with one of the parent forms containing 1AL/1RS translocation and combination K.17 (Remeslivna / Smuglyanka) with two translocations were characterized with the same effects. The lowest rate was in K.25 (Rozkishna / Epoha odes''ka), where the parent forms do not contain translocations in their henotype. Also, this index was negative (-8,22) in inverse combinations (K.10). Studying the nature of phenotypic inheritance of the main ear length it was found out that from 30 hybrid combinations overdominance appeared in 5 (17 %), partial positive dominance in 3 (10 %), intermediate inheritance in 10 (33 %), partial negative inheritance in 10 (33 %), depression in 2 (7 %). It should be mentioned that the indices of phenotypic overdominance as a high true heterosis were observed mainly in combinations formed with wheat-rye translocations (K.15, K.27, K.11 and reciprocal K.26). These inverses combinations (except K.11 and K.26) to the above mentioned group with overdominance had a disposition of nearby class inheritance - partial positive dominance (K.17 - Remeslivna / Smuglyanka) and intermediate inheritance (K.22 - Rozkishna / Kryzhynka). It should be noted that depression showed reciprocal combinations (K.3 and K.18 - Myronivs''ka rann''ostygla / Remeslivna) according to the index of the main ear length where one of the parent forms is carrier of 1BL/1RS translocation. Manifestation of true heterosis and overdominance according to the length of the main ear is observed in most combinations in which parent forms contain 1BL/1RS or 1AL / 1RS translocation in their genotype. According to the results of analysis the best hybrid combinations as for «the length of the main ear»: with the 1BL/1RS - Kryzhynka / Rozkishna; with both of translocations - Smuglyanka / Remeslivna and reciprocal combination Kryzhynka / Smuglyanka; without translocations - Myronivs''ka rann''ostygla / Rozkishna. The combination of the parent forms, which are carriers of wheat-rye translocation effects positively on the formation of the main ear length and foreknows successful work as for creation of new patterns that become carriers of wheat-rye translocations. Hybrids can form dense ear, which will give possibility to get highly productive plants despite the low expression of overdominance as for the studied traits