Determination of cold resistant turkish red pine (Pinus brutia Ten.) families sampled from different breeding zones

In this study, it was aimed to reveal the cold hardiness variation of the families of three different origins from different breeding zones. Cold hardiness tests were carried out in winter and spring. Nine different temperature levels except for the control group (+4°C) were used in both seasons. Tests were carried out on shoots obtained from 1+0 year-old seedlings obtained from 54 different families. The cold damage in the shoots was determined by both the chlorophyll fluorescence and visual observation method. The temperatures at which cold damage starts in families were tried to be revealed both with Lethal Temprature 50% (LT50) values calculated using the non-linear model and with the multiple comparison test (Dunnet). Genetic parameters (heritability, genetic variation coefficient) and breeding values were estimated using the data at the critical temperature (p<0.001) levels in both seasons. As a result of the research, a statistical difference (p< 0.0001) was found between families. According to the Dunnet test results, the frost damage temperature range in winter was -17.5°C – 22.5°C, and in spring it was -15°C - 17.5°C. With the non-linear model, the highest and lowest LT50 values were calculated as -23.25°C and -18.60°C in winter, and -17.78°C and 15.02°C in spring, respectively. Individual and family mean heritability were estimated as 0.35 and 0.57 in winter, and 0.47 and 0.64 in spring. The family with the highest breeding value is 3234 in spring, while 3236 is in spring. Spearman's rank correlation coefficients of LT50 values with breeding values was calculated as 0.93 in winter and 0.98 in spring. From now on, studies for cold hardiness in forest tree species carried out as family based and the number of temperature levels should be determined according to the purpose of the study. Cold hardiness characteristic should also be taken into account in the red pine breeding program considering the changing climatic conditions.