Evaluation of freezing stress tolerance in promising durum wheat and its relationship with physiological traits and molecular markers

Cold tolerance in wheat is one of the most important factors effective in the field of winter damage in Iran. Freezing and laboratory tests were carried out in the greenhouse and plant breeding laboratory of Mohaghegh Ardabili University in 2018-20 to achieve the set goals. The plant materials used included 45 promising durum wheat lines. Durum wheat genotypes were planted in a randomized complete block design with three stress levels. The results of the variance analysis of LT50 showed a significant difference between the genotypes at the probability level of 1%. LT50 varied between -0.754 and -26.609 values. The survival percentage of plants decreased with increasing stress. In clustering based on the LT50, the genotypes were divided into 5 groups. The dendrogram obtained from the cluster analysis based on all the traits divided lines in the control level, -8 °C, -10 °C, and -12 °C into 8, 6, 9 and 7 different groups. Four factors were identified in the control level, 5 in the first stress, 6 in the second stress, and 5 in the third stress level. To evaluate the relationship between the measured traits and RAPD molecular markers, stepwise multiple regression analysis was performed and significant relationships were observed. LT50 showed a correlation with 9 markers. Finally, according to the tests conducted, lines 1, 2, 3, 4, 5, 6, 7, 8, 10, and 23 were recognized sensitive lines and lines 11, 12, 13, 14, 15, 17, 18, 19, 21, 29, 31 and 27 were recognized as resistant.