Evaluation of barley genotypes to cold stress

In order to evaluate cold tolerance of 20 barley genotypes under field conditions an experiment was carried out with randomized complete blocks design at 3 sowing dates of October 5, November 5 and December 5 in Saatlu agricultural research station of west Azerbaijan province during 2011-12 seasons. Also, another experiment was done on the same genotypes based on completely randomaized design under greenhouse conditions. Cold stress performed until -25°C at two, four and six leaves stages. Traits of LT50, ion likage and dry matter were measured and apex photographed. Field experiment results showed the lowest significant diffrernces at p0.05 probability between different levels of sowing date, genotype and intraction between them for traits of plant height, spike/m2, kernel per spike, 1000-kernel weight, grain yield and total dry matter. Genotypes with winter growth type had higher grain yield (4250kg/ha) than spring growth type (4190kg/ha). There were significant differences for ion leakage and dry matter at 4 and 6 leaves stages under greenhouse conditions. Genotype of 1 with winter growth type and lowest values of range and standard diviation for grain yield, total dry matter had LT50=-38°C and low ion likage. In contrast, genotypes of 5, 10 and 14 with spring growth type were identified sensitive to cold stress due to having more values of range, standard diviation for grain yield and total dry matter, LT50=-18 to -27°C and ion lokage 25 to 33µd/m. At regression analysis, 1000-kernel weight and total dry matter remained at final model. Cluster analysis showed that genotypes of 2, 18, 1, 17 and 19 were superior genotypes. In principal component analysis, four components showed 80% of total variations and frist component with 26% of variation as yield component was important for selection at improving grain yield of genotypes. In conclusion grain yield of winter and spring barley genotypes were affected by different planting dates.