Developing the optimal conditions for in vitro propagation of European chestnut

The forest ecosystems are of special significance for conservation of biodiversity of Georgia. The forest covers 39,9% of the territory of the country. Their greater percentage (98%) is presented by mountainous forests. They have water regulating, soil protective, climate stabilizing functions. At the same time the forest is an important location of many relict, endemic and threatened species of plants and animals. Hence, conservation of forest ecosystems plays a fundamental role in order to prevent the loss of plant species with ecological and economic importance. Chestnut (Castanea sativa Mill.) is the dominant of mountainous forests of Western Georgia (150-1800 m), which occupy the most percentage of areas covered with forests (approx. 75%). At present, due to low self-renewal and diseases the big massifs of chestnut forests in Tkibuli district are on the verge of destruction. Traditional ways of chestnut reproductions are complex and full of drawbacks; hereafter in vitro propagation is sound alternative for traditional breeding system. In this study, an attempt was made to establish the optimal conditions for chestnut’s micropropagation via zygotic embryogenesis and estimate growth and viability of in vitro derived plants. The results showed that plants derived from zygotic embryos had good capacity of proliferation. 0.4 μM BAP in combination with activated charcoal was the best growth regulator for shoot elongation. MS culture medium supplemented with 0.4 μM BAP and citric acid was the best shoot proliferation. Rooting of in vitro plantlets was achieved on MS medium supplemented with 15 μM IBA showing 60% intensity and was the most efficient in terms of secondary root production. Plantlets with multiple and shorter root systems have higher viability index. We suppose that the above study will contribute to the protection of rare and endangered plant species using biotechnological approaches, thus preserving diversity of the forest ecosystems.