Abstract:

Determination of drought adaptation strategies on plant species is highly important to develop resistant cultivars. Drought resistance mechanisms known as drought escape, avoidance and tolerance should be investigated and associated with several mathematical indices in especially tree species. Therefore, the major aim of this study was to identify drought adaptation strategies with these indices for tree species by using poplar as a model organism. Black poplar clone collection including 300 individuals collected from all around Turkey was tested in a field trial. The growth and biomass production capacities of these individuals with several physiological traits were measured and compared in rainy and drought periods. Mean Relative Performance (MRP) and Stress tolerance Index (STI) were used to identify adaptive responses of black poplar to drought stress. In the study, MRP favored drought tolerant genotypes having the highest biomass production. Genotypes with higher STI values exhibited drought avoidance mechanism which characterized with low productivity but much higher drought resistance. On the other hand, lower STI was associated to drought escape genotypes which revealed the lowest growth performance and the highest defoliation rates under drought. In the current study, relationship between antioxidant enzyme activities and drought adaptations were also investigated on the leaves of selected clones. Higher enzyme activates associated with drought escape strategy in the study.

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