The general transcription repressor, TaDr1 gene, was identified during screening of a wheat SNP database using the Amplifluor-like SNP marker KATU-W62. Together with two genes described earlier, TaDr1A and TaDr1B, they represent a set of three homeologous genes in the wheat genome. Under drought, the total expression profiles of all three genes varied between different bread wheat cultivars. Plants of four high-yielding cultivars exposed to drought showed a 2.0–2.4-fold increase in TaDr1 expression compared to controls. Less strong, but significant 1.3–1.8-fold up-regulation of the TaDr1 transcript levels was observed in four low-yielding cultivars. TaVrn1 and TaFT1, which controls the transition to flowering, revealed similar profiles of expression as TaDr1. Expression levels of all three genes were in good correlation with grain yields of evaluated cultivars growing in the field under water-limited conditions. The results could indicate the involvement of all three genes in the same regulatory pathway, where the general transcription repressor TaDr1 may control expression of TaVrn1 and TaFT1 and, consequently, flowering time. The strength of these genes expression can lead to phenological changes that affect plant productivity and hence explain differences in the adaptation of the examined wheat cultivars to the dry environment of Northern and Central Kazakhstan. The Amplifluor-like SNP marker KATU-W62 used in this work can be applied to the identification of wheat cultivars differing in alleles at the TaDr1 locus and in screening hybrids.

РезюмеНа основе полевых испытаний, анализа наследования количественных признаков и молекулярно-генетического скрининга выделены наиболее удачные гибридные комбинации. В качестве лучших по степени доминирования над родительскими формами выделены комбинации♀Акмола 2 ×♂Омская 30, ♀H 749-4× ♂Акмола 2, ♀Br.LineZ2 × ♂Саратовская 60, ♀Br.LineZ2× ♂Карагандинская 31,♀Алтайская жница × ♂Br.LineZ2, ♀MMF 177 × ♂Алтайская жница. У данных гибридов, за исключением неполного доминирования у комбинации ♀Br.Line-Z2 × ♂Карагандинская 31, проявлено 100% сверхдоминирование по массе 1000 зерен и количеству зерен в колосе над родительскими формами. В результате изучения трансгрессивного расщепления, выявлены гибриды F2: ♀Карагандинская 70 × ♂ Line-20, ♀Шортандинская 95 × ♂Омская 30. Положительную трансгрессию по слабо наследуемому показателю продуктивной кустистости проявили две комбинации гибридов F2: у комбинации ♀Карагандинская 70 × ♂ Line-20 положительная трансгрессия над родительскими формами составила 12,5%, у гибрида ♀Карабалыкская 92 × ♂Br.Line-S27 100%.Слабый характер наследования признаков продуктивности выявлен у комбинации Актюбинка × H1142. Трансгрессивное расщепление по показателям озерненности и массы зерна с колоса проходило практически идентично во всех комбинациях. Наиболее удачными гибридными комбинациями в обоих случаях оказались ♀Карабалыкская 92 × ♂Br.Line-S27 с более высокой трансгрессией по озерненности колоса (52,9%), и ♀Карагандинская 70 × ♂Line-20 странсгрессией по массе зерна с колоса в 69,3%. В результате скрининга по маркеру KATU W-51, разработанному для гена TaDr1, выделены комбинации Терция × Br.Line-Z3, Шортандинская 95 ул. × Br.Line-F45, Шортандинская 95 × H1142-1.В ходе комплексного отбора с помощью гибридологического, селекционно-генетического анализа и молекулярного скрининга удалось выявить наиболее удачный гибрид ♀Карабалыкская 92 × ♂Br. Line-S27 с положительной трансгрессией по основным показателям продуктивности. Ключевые слова: Селекция, яровая пшеница, ген, гибрид, засуха, сверхдоминирование, трансгрессивное расщепление, генотипирование, отбор.

The article presents the results of research on the selection of spring wheat inthe conditions of Northern Kazakhstan. Field trials have been carried out and anassessment has been made for the F1 and F2 generation hybrids obtained by crossing.Evaluation was carried out on 29 hybrid combinations, the parental forms of whichwere local varieties allowed for cultivation and foreign genotypes.The quantitativeassessment included indicators of productive bushiness, graininess, grain weight perear and 1000 seeds weight.Selection based on genetic information was carried outusing the KATU W-51 marker developed for the TaDr1 gene of a transcriptionrepressor involved in the adaptation mechanism in response to drought. The mostsuccessful hybrid combinations of interest in terms of drought tolerance andproductivity in contrasting moisture conditions in Northern Kazakhstan have beenidentified.These hybrids were distinguished by over-dominance and positivetransgression over the parental forms when inheriting traits. The combinations♀H749-4×♂Akmola 2, ♀Br.Line-Z2×♂Saratovskaya 60, ♀Br.Line-Z2 ×♂Karagandinskaya 31, ♀Altayskaya zhnitsa × ♂Br.line Z2, ♀MMF177 ×♂Altayskaya zhnitsa were identified as the best F1 hybrids in terms of the degree ofdominance over parental forms. Hybrids F2♀ Karabalykskaya 92 × ♂Br.Line - S27,♀Karagandinskaya 70 × ♂Line-20 were distinguished by positive transgression for aweakly inherited trait of productive bushiness. According to the indicator of the massof 1000 seeds positive transgression was shown by the combinations♀Shortandinskaya 95 × ♂Omskaya 30, ♀Karabalykskaya 92 × ♂Br.Line-S27,♀Akmola 2 × ♂Omskaya 30, ♀Aktyubinka × ♂Н1142, ♀Erythrospermum ×♂Br.Line-S45. As a result of genotyping, hybrids were identified that showed gooddivision into alleles: Tertsiya× Br.Line-Z3, Karabalykskaya92 × Br.Line-S27,Shortandinskaya 95 ul. × Br.Line-F45, Shortandinskaya 95ul. × H1142-1