Effects of acclimation on wheat (Triticum aestivum L.) cold tolerance under laboratory conditions

Sever coldness causes damage to the wheat and affect its growth and yield, thereby this experiment was conducted in controlled conditions to investigate freezing tolerance of 29 wheat genotypes. Acclimation treatments (in two levels: acclimation and non-acclimation) were considered in the main plot and combination of temperature (0, -4, -8, -12, -16 ◦C) and genotypes as sub plot. Survival percentage, dry weight and plant height were measured four weeks after freezing in the glasshouse. All these traits were affected significantly by freezing treatments (P<0.001). Reducing temperature under -8 ◦C caused a significant reduction in the wheat survival percentage. Acclimation alleviated the effects of freezing, so that at -12 ◦C in non-acclimation conditions, dry weight was 72.1 mgr, but it reached to 144.9 mgr in acclimation conditions. Lethal Temperature 50 (LT50) was lower than -15 ◦C in 14 cultivars and higher than -15 ◦C in 15 cultivars. Among studied genotypes, Alamout, Bezostaja, Falat, Glenson and MV-17 were more cold tolerant than others. In order to determine the cold tolerance of genotypes, conducting complementary experiments in controlled and field conditions could be useful.