SEED GERMINATION AND JUVENILE GROWTH OF THUYA PLANTS (Tetraclinis articulata Vahl Masters) FROM FIVE ORIGINS OF MOROCCO

Tetraclinis articulata Vahl Masters is a forest species endemic to the western Mediterranean, which is of great ecological, socio-economic and environmental interest. However, its stands are subject to a process of degradation increasingly accentuated, associated in addition to the scarcity of natural regeneration. The rehabilitation of the ecosystems of this species necessarily involves reforestation. But the success of the plantations carried out so far remains below the set objectives. But the success of the plantations carried out so far remains below the objectives fixed. The choice of more suitable provenances and more efficient growth contributed to the improvement of plantation success. The objective of this work is to study the effect of provenance on seed germination and juvenile growth of Thuya seedlings in a forest nursery. The analysis of the results obtained revealed that the best germination rates, of the order of 93, 87 and 72 %), were recorded for seeds collected in the region of Tafoughalt, Chaouen and Oued Beht. The evolution of the morphological parameters and the analysis carried out on the Thuya plants after 16 months of stay in the nursery, showed that the origin of the seeds influences considerably the development of these plants. The variability in performance concerns plant height (33 to 47.5 cm), collar diameter (6.3 to 8.9 mm) and the average number of leaves per plant (32 to 42); these values ​​are increasing from Beni Souhane to Tafoughalt. It also relates to the total length of the roots (55 to 73 cm) which increases from Chaouen to Oued Beht. The ratio root length to height is also a source of variability (1.22 to 2.07) with the highest ratio recorded at Beni Souhane. The ratio root length to biomass varies from Ouzoud to Oued Beht (1.02 to 1.41g). The three most successful provenances are those of Tafoughalt, Chaouen and Oued Beht. These results constitute the first step to control the production techniques of Thuya plants which must be confirmed through the monitoring of the behavior and the survival of Thuya plants in the different provenances in the field.