Chlorophyll Fluorescence-Based Studies of Frost Damage and the Tolerance for Cold-Induced Photoinhibition in Freezing Tolerance Analysis of Triticale (xTriticosecale Wittmack)

Freezing tolerance of 60 breeding lines of winter hexaploid triticale (xTriticosecale Wittmack) was studied in the field-laboratory experiment. The experiment was repeated over three winters. The survey was also carried out in plants grown and cold-acclimated in the laboratory. In both the experiments, plant survival analysis and chlorophyll fluorescence-based studies on energy flows in photosystem II (PSII) (JIP-test) after freezing of detached leaves were performed. In the laboratory experiment, the temperature of 50 % electrolyte leakage from leaves and the resistance against cold-induced photoinhibition were additionally investigated. In the case of plants' cold-acclimated in the field, determination of the freezing tolerance of PSII gave similar results as the determination of freezing tolerance of whole plants. Both traits were strongly affected by genotype-environmental interactions, but these effects were less visible for PSII characteristics. In the laboratory experiments, a strong correlation between freezing tolerance and the tolerance for cold-induced photoinhibition of photosynthesis was observed. The possibility of the use of chlorophyll fluorescence-based techniques for the determination of freezing tolerance in triticale is discussed.