Some biochemical traits related to cold tolerance in different bread wheat cultivars with different growth types in Kermanshah region

Wheat has more distribution range than any crop in the word due to its wide adaptation to different climatic conditions. Occurrence of environmental stresses during wheat growth period significantly reduces its yield in most of its cultivated areas. Among different stresses, cold stress is one of the environmental factors that limiting the cultivation of wheat in the cold and the mountainous areas. Cold stress causes changes in physiological and biochemical traits in plants. This research was conduct to evaluation of some physiological and biochemical traits that related to cold tolerance in different wheat genotypes in semi cold winter region.

This study was conducted at research farm and laboratory crop physiology, Department of Plant Production and Genetics, Razi University, Kermanshah, Iran during 2013-2014 cropping cycles. The farm experiment was a Randomized Complete Block Design (RCBD) with three replications. Sowing date was mid-November. The purpose of field cultivation was to induce the normal induction of cold acclimation in different wheat cultivars under natural field conditions. In this research 12 bread wheat cultivars such as: Norstar, Zarin, Kavir, Baz, Sivand, Alvand, Pishgam, Pishtaz, Orum, Shahryar, Bahar and Parsi were evaluated. These cultivars were purposefully selected from different wheat growth types of spring, autumn and qualitative cultivars. Then, at different stages of cold acclimation, the crowns of the studied cultivars were transferred to the laboratory and in order to evaluation of physiological traits were studied under different temperatures in thermogradient freezer. To this end, a Factorial experiment based on Completely Randomized Design (CRD) with three replications was used. In this experiment, the first factor was 12 above mentioned wheat cultivars, and second treatment was five temperature treatments (+3, -3, -6, -9 and -12 ○C).

The results showed that, winter and facultative cultivars had more crown soluble proteins, membrane stability and antioxidant enzymes activity (peroxidase, superoxide dismutase and catalase) than spring cultivars. The LT50 average was -6.5 ○C. In the meantime, LT50 in winter and facultative wheat cultivars was -8.5 ○C and in spring cultivars was -4.7 ○C. The soluble proteins and catalase activity had the highest positive and significant correlation with cold tolerance.

In general, physiological and biochemical characteristics in winter and facultative cultivars (Norstar, Zarin, Orum, and Alvand) were more associated with cold tolerance than the others. In this research, Norstar cultivar with LT50= -14 ○C and Orum cultivar with LT50= -11.5 ○C were identified as resistant cultivars to cold stress.