مشخصات پژوهش

In order to investigate cold tolerance in 20 barley genotypes based on crown survival percentage, a greenhouse experiment was conducted as split plots with three replicates, with temperatures (-8, -10, -12, -14 and -16°C) as main plots and barley genotypes constituting subplots. Randomized complete block design was performed to analyze physiological traits measured after acclimation and before applying chilling temperatures. Crown survival percentage was measured zero at -16°C. Error was not significant for main factor in split plots, therefore, data analysis for -8, -10, -12 and -14°C was executed as factorial. Results indicated that temperature, genotype and their interactions had significant influence on the crown survival percentage. Also, the genotypes were significantly different in terms of LT50, the glycine betaine content and leaf relative water content before and after adaptation to cold. Comparison of the means, based on LT50 and crown survival percentage, suggested the genotype number 15 (with K-096M3 pedigree) as the most tolerant to crown freezing, and genotypes 36 (Schulyer), 15 (K-096M3) and 14 (GK Omega) as possessing the most desirable physiological traits, with genotypes 15 and 36 possessed the lowest difference before and after leaf relative water content, and the maximum quantity of glycine betaine after adaptation to cold. Cluster analysis of the genotypes, based on the aforementioned traits, divided them into three distinct tolerant, semi- tolerant and sensitive groups.