Teak

Abstract

Teak (Tectona grandis Linn f.) is one of the world's premier hardwood timbers, possessing excellent properties. It has been extensively planted within Asia, its natural range, and throughout the tropical regions of the world, including Pacific, Africa, and Latin America. Teak breeding programs started with selection of superior phenotypes (plus trees) in both natural and established plantations. These selections were made based mainly on their phenotypic appearance. Some help was obtained from the molecular marker identification but only in the last 15 years. Conventional breeding methods have shown to have certain limitations in this species, including long rotation age, difficulties in performing controlled pollination, low germination percentage, and low genetic variability of the species. These limitations make genetic engineering an important tool. Despite the progress made in the last 20 years by using plant molecular approaches to improve some forest trees, the success of teak transformation has been limited. Although some achievements have been made (Agrobacterium susceptibility in teak was tested; the first experiments with transient expression were carried out successfully; identification of genetic markers has been initiated with some progress), the low capacity to regenerate from somatic tissues has obstructed the continuity in transgenic experiments. This limitation has reduced the capacity of the whole transformation process. It is expected to overcome this barrier in order to improve the transformation efficiency.