Prediction of Establishment in Progenies of Persian Oak Trees Based on the Morphological and Chlorophyll Fluorescence Traits

The regeneration of trees in forests with a long dry season such as Zagros has extreme difficulties. Predicting of water deficit tolerance in the progenies based on the geographic, vegetative and physiologic characteristics such as the performance of photosystem can conducted to increasing the efficiency of plantations.

In this study, the progenies of 40 Persian oak trees derived from 8 populations located in southern Zagros forests were assessed for water deficit tolerance based on their geographic, growth and physiological characteristics such as photosystem II under greenhouse conditions. Also, the percentage of seedling establishment for each mother tree were evaluated by field trial during two years. The corresponding data obtained from these experiments in accompanied by the morphological characteristics of leaves and seeds of mother trees were used to developing of the predictive models of seedling establishment in the field. In this research, greenhouse and forest field experiment was conducted to evaluate the response of Persian oak seedlings to drought stress based on some indicators of stress resistance from photosystem II. Persian oak seedlings from different mother trees were subjected to drought stress by stopping irrigation for one month in the greenhouse conditions. Then, the seedlings were irrigated for one month again and in all stages, the photosystem II, the percentage of leaf yellowing and the percentage of survival of the seedlings were recorded. Also, the establishment of the offspring of mother trees in the forest field was evaluated based on the percentage of survival and the height of the seedlings during two years, and their relationship with the leaf and seed morphological characteristics of the mother trees was investigated.  

The results showed that there is a positive relationship between the percentage of survival, and stress resistance indicators in greenhouse conditions with the percentage of survival and the height of seedlings in the forest field. Also, seedlings from drier seed origin, lower altitudes and latitudes, had higher drought resistance in greenhouse conditions. However, none of the growth and survival parameters in the field was related to the environmental characteristics of population. The relationship between the leaf and seed morphological characteristics of mother trees with stress resistance and the establishment of seedlings showed that the seedlings grown from wider and heavier seeds had better growth characteristics and survival only in the first year. Also, some leaf morphological characteristics of mother trees, such as petiole length, tooth width and number of veins were affecting traits to seedlings successful establishment in the forest field.

The results of this research showed that collecting of larger seeds from mother trees with suitable leaf traits could be effective for reforestation success. In addition, the use of physiological traits in the control condition in greenhouse can help for selecting the resistant progenies from superior populations or mother trees.