تحمل به يخبندان ژنوتيپ هاي اميد بخش گندم به روش يخبندان طوقه (Crown freezing)

Study of Frost Tolerance in Promising Wheat genotypes Using Crown Freezing method

Liens tolerate environmental stresses utilizing is one of the applicable technologies in sustainable agriculture. Since occurrence of a suitable winter for studing and selection of cold/frost resistance on breeding materials is one year out of ten, therefore laboratory methods complementing field data provide a reasonable solution for this propose. This research was conducted in Khorasan Agri. Res. Center. Mashhad. Using RCBD in three replications during 1380-81. Treatments consisted of twenty promising genotypes of uniform regional yield trail (cold area). Genotypes suits low temperature regions will be introduced based on generated results from this investigation. Using crown freezing method, experimental genotypes were treated with -20° C temperature under controlled conditions. Survival percentage was computed. Results indicated that genotypes No.9 (C-78-9) and No.7(C-78-7) had highest (98.33%) and lowest (66.67%) survival percentage respectively. The minimum Crown Moisture Content was detected in line No. 9 (C-78-9) and there was no significant difference for the same trait between genotype No.7(C-78-7) and other superior genotypes. A high negative correlation (r = -0.701) was observed between survival percentage after exposing to frost and crown moisture content. Ear primordia development stage was one of the characters which had also a significant correlation with survival percentage (r = -0.619). Significant correlation between survival percentage and days to heading (r =-0.207) and days to physiological maturity (r =-0.028) was not observed. Correlation between survival percentage and collected cold damage data from experimental fields over five low temperature regional stations was highly significant (r =0.416), therefore it may be concluded that Crown Freezing Method and subsequent computing of survival percentage is a reliable method for estimating wheat frost/cold tolerance in natural conditions.