Drought tolerance of some anatolian black pine [pinus nigra j.f. arnold ssp. pallasiana (lamb.) holmboe] provenances at seed and seedling phases

In this study, the effect of drought stress on seed and seedlings of Anatolian Black Pine (Pinus nigra Arnold. ssp. pallasiana) were studied. Seed and seedlings of Nallıhan, K. Hamam, Çerkeş, Dursunbey, M. K. Paşa and Yılanlı origines were used for the measurements. To evaluate the impact of drought stress on seeds, the germination rate and germination percentage of seeds subjected to different levels of drought stress (0, -0.2, -0.4, -0.6, -0.8 MPa) using PEG 6000 solution were determined. The impact of drought stress on seedlings was evaluated through monthly measurements of morphological (seedling height, root collar diameter) and of physiological (Photosynthetic efficiency and water potential values) characteristics of the seedlings subjected to 3 different irrigation regimes (every day, every 5 days, every 10 days) in the greenhouse between April and September 2018. Additionally, the survival rates of the saplings were determined at the end of September. The germination percentage and germination rate of seeds decreased as water stress levels increased. Seeds from Nallıhan, K. Hamam and M. K. Pasha origins showed higher germination values at low water potential levels such as -0.4 and -0.6 MPa compared to other origins. The intra-species variation among the origins has been confirmed statistically too. In the drought tests at the seedling stage, differences were found between the origins in terms of morphological characters at different levels of water stress, whereas only the water potential values of physiological characters were found to differ between the origins. As the level of irrigation stress increased, diameter and height and water potential of seedlings were decreased in general. Nallıhan, K.Hamam and Çerkeş origins were less affected from drought stress in morphological and physiological terms. When the all drought tests of the origins evaluated together, the Nallıhan, M. K. Paşa and K. Hamam origins demonstrated a more drought-resistant attitude under water stress.