Reciprocal substitutions analysis of freezing resistance in wheat (Triticum aestivum L.)

To investigate the effects of individual chromosomes on freezing resistance, as well as their interactions with the genetic background, reciprocal sets of chromosome substitution lines between two hard red winter wheat cultivars, ‘Cheyenne’ and ‘Wichita’, were used in this study. Duplicate lines for each chromosome were included to check background homogeneity. Two experiments were carried out in complete block designs with two replications for each duplicate. Crown and leaf water content and leaf wet weight were measured in the field experiments. Crown survival, electrolyte leakage and 50% lethality temperature (LT50) were measured in the laboratory. The results showed that ‘Cheyenne’ was more resistant than ‘Wichita’. Crown survival was significantly correlated with crown water content, crown wet weight and electrolyte leakage. Chromosomes 6A, 3B and 5D substituted from ‘Wichita’ into ‘Cheyenne’ (‘CNN‐WI’), decreased the crown survival, and increased membrane stability, crown water content and crown wet weight of ‘Cheyenne’. Thus, these chromosomes from ‘Wichita’ decreased freezing resistance in ‘Cheyenne’. Reciprocally, chromosomes 5A, 5D, 3B and 4D from ‘Cheyenne’ into ‘Wichita’ increased crown survival and decreased crown water content and crown wet weight of ‘Wichita’. It was concluded that these chromosomes from ‘Cheyenne’ cause freezing resistance in ‘Wichita’ and carry freezing‐resistance genes.