Frost resistance of new bread winter wheat varieties of Myronivka breeding

Purpose. To identify high frost-resistant samples of winter wheat to be used as sources of this trait in breeding. Methods. There were studied the varieties of bread winter wheat of Myronivka breeding Balada myronivska, Hratsiia myronivska, MIP Dniprianka, MIP Assol, Estafeta myronivska, Vezha myronivska transferred to the State Qualification Examination for Evaluation of Suitability for Dissemination in Ukraine in 2016. Evaluation of frost resistance was carried out according to the conventional method of DSTU 4749: 2007. The variety Myronivska 808 was used as the standard of high frost-resistance. Significance of the difference in frost resistance between the standard mentioned above and the varieties under study was tested according to the Fisher criterion. Results. Freezing wheat plants in low-temperature chambers under the regime -18 °С in 2017 showed that the varieties Balada myronivska, Hratsiia myronivska, MIP Dniprianka, and Vezha myronivska by the percentage of survived plants were at the level of the high frost-resistant variety Myronivska 808, while the varieties MIP Assol and Estafeta myronivska reliably exceeded the standard. Freezing at -20 °С has revealed that frost resistance of the varieties studied was at the level of Myronivska 808. In 2018 after freezing at -18 °C, the percentage of survived plants at the level of the standard was noted in the varieties Balada myronivska, Hratsiia myronivska, and MIP Assol. At this temperature of freezing frost resistance of the variety Estafeta myronivska was significantly higher than the standard. The variety Hratsiia myronivska was distinguished with frost resistance at the level of the variety Myronivska 808 for both freezing regimes. In the winter wheat varieties MIP Dniprianka and Vezha myronivska at the temperature of freezing -18 °С, the percentage of survived plants significantly exceeded the variety Myronivska 808, and at -20 °C this index did not significantly differ from it. Conclusions. The two-year results of freezing plants of new bread winter wheat varieties of Myronivka breeding showed high level of their frost resistance. The varieties MIP Dniprianka, MIP Assol, Estafeta myronivska, and Vezha myronivska are recommended to be use in winter wheat breeding as source of frost resistance.