In order to evaluate the electrolyte leakage as an indicator of freezing injury in colza (Brassica napus L.) genotypes under controlled conditions, a trial carried out at the greenhouse of College of Agriculture, Ferdowsi University of Mashhad. In this study 10 rapeseed genotypes, with 5 temperatures (0, -4, -8, -12 and -16 °C) on subplot and acclimation and non acclimation on main plot were evaluated on RCD factorial split plot with two replications. Plants were kept until 3-5 leaf stage in greenhouse condition with 23/162 °C (day/night) and natural photoperiod. Pots were subjected to acclimation (for three weeks) or non acclimation that plants immediately frozen.For acclimation treatment after three weeks freezing was done in thermogradient freezer. The cell membrane integrity was measured through electrolyte leakage and the lethal temperature 50 (LT±50) of samples also were determined. There were significant differences (p<0.05) among acclimation, genotypes and freezing temperatures. As temperature decreased, electrolyte leakage of all genotypes were increased. Acclimation decreased the LT50 of all genotypes. In non acclimation SLMO46 and Symbol genotypes showed the highest and the lowest freezing tolerance, respectively.On the other hand in acclimation treatment Licord and Okapi had the lowest and the highest LT50, respectively.

کلمات کلیدی