During the period 2019 - 2024, a study on the frost resistance and grain yield of 40 breeding lines and standard varieties of common winter wheat was conducted. The breeding lines were created through the method of intervarietal hybridization in IPGR-Sadovo, Bulgaria. Frost resistance was assessed by controlled freezing in a temperature-regulated chamber. As standards were used varieties Mironovska 808, Pobeda, Bezostaya 1, Rusalka, N 301 and San Pastore, which possess different level of the frost resistance. The average values were obtained based on plant survival rate after exposure to temperatures reaching to -18°C. The breeding lines ranking was determined using the calculated confidence interval for each standard based on the obtained data. The productivity was evaluated after experimental cultivated and harvested to four replications per growing period. The lines productivity was compared to the standard variety Sadovo 1 through computed ANOVA analysis. The highest frost resistance was found for the breeding lines МH 270/27, МH 268/1008 (Sashez), RU 32/2072,73,74 (Yailzla), MH 187/3 (Nadita), RU 77/878, RU 128/2900, RU 82/1476, RU 93/1895, RU 79/1373, МH 260/1175, BA 769, BA 861, BA 665, BA 535, BA 968 and BA 578 (Blan). Taking into account the expressed frost resistance and parameter grain yield, it could be concluded that the breeding lines MH 268/1008 (Sashetz), RU 32/2072,73,74 (Yailzla), RU 76/1321, RU 33/3244, MH 260/1175, BA 769, BA 665, BA 535 and BA 578 (Blan) combine high frost resistance and productivity.
Chipilski et al. (Thu,) studied this question.