Intraspecific variability in cold hardiness of Taurus cedar (Cedrus libani A. Rich.) in Turkiye

To better guide Cedruslibani provenances movement to northerly and higher-altitude sites for afforestation, the limits of hardiness to cold should be better known. In this study, we quantified the cold hardiness of seven C.libani provenances sampled from a provenance trial in Ankara, Turkiye, a site located outside the natural range of distribution of the species. Visual damage observation and chlorophyll fluorometry screening methods were used to assess variation in cold hardiness (LT50, the temperature estimated at which 50% of the needle tissue is damaged) among populations. Overall, C.libani can tolerate winter temperatures down to - 21.5 degrees C. Even though there were significant differences in cold hardiness among populations, the maximum difference was only 1.9 degrees C between the most and the least cold-resistant provenances. Cold tolerance was generally greater for provenances that experienced colder temperatures in March and lower levels of total precipitation in their native ranges. We also conclude that the fluorometry method provides a more efficient and stable comparison of cold hardiness than visual observation for C. libani. The results of this study may be useful for assisted migration and breeding programs, as well as for developing guidelines for genetic materials transfer, to increase productivity or adaptability of C. libani.