Investigation on genetic variation of teak (Tectona grandis Linn. f.) in Myanmar for the sustainable utilization and conservation of genetic resources

Tectona grandis, commonly known as teak, is one of the most famous tropical tree species. It belongs to the family Verbenaceace. Teak naturally occurs in India, Laos, Thailand and Myanmar. The total area of natural teak forests in those countries are about 28 million ha and the largest area of teak forests lies in Myanmar, having about 16.5 million ha.
Nowadays, teak forests in Myanmar are under enormous threats due to extremely high deforestation rate and accordingly, genetic resources of teak become endangered. Therefore, conservation and sustainable utilization of these genetic resources is urgently needed. Nonetheless, comprehensive genetic information of teak forests is still not available. Thus, investigation of genetic resources of teak forests becomes an integral part for the sustainability of teak forests in Myanmar.
With the advent of molecular markers, many genetic studies can be performed with ease nowadays. Genetic variation of teak has been investigated using different molecular markers such as AFLP, RAPD and SSR in some countries. Nonetheless, none of these studies covered the whole natural range of teak forests. More importantly, teak from Myanmar was always missing in those studies.

This study will be performed in order to
• examine genetic variation patterns of teak in natural populations revealed by microsatellite markers, AFLPs and cpDNA markers
• examine the impact of management operations on the genetic structures of teak by comparisons of genetic structures of unmanaged and managed teak forests
• investigate genetic differentiation among natural regeneration and adult teak trees
• compare genetic structures of teak in Myanmar with diversity in other areas of the distribution of teak
These results will be used to
• provide comprehensive scientific information for management and conservation of genetic resources of teak in Myanmar
• propose comprehensive guidelines for collection of reproductive material for plantation programs
• provide a basis for the development of methods to reliably distinguish teak from Myanmar from teak of other regions

Sampling was carried out in Myanmar from October 2009 to January 2010. A total of 1600 samples were collected from eight population pairs from 8 different regions of the country. In one region, managed natural population and unmanaged natural population were selected. In each population, 50 samples from adult trees and also 50 samples from young seedlings were collected. Apart from samples from Myanmar, 80 samples from Benin were also collected. Additionally, samples from India, Thailand and Indonesia are planned to add for the study.
DNA isolation was carried out using Qiagen Plant Minikit protocol. Out of the fifteen SSR primers, eleven polymorphic SSR primers was selected for the whole SSR analysis after performing preliminary tests using a few samples from different geographic regions.
Currently, analysis of SSR for adult teak trees has been completed and of SSR for teak seedlings is also about to complete shortly.