In vitro growth differences for potential teak clonal selection

Sprouting buds from twenty six superior teak clones selected from mature trees in Teak Improvement Centre were cultured for preparing uniform shootlets to be used in this study. Top of the in vitro shootlets obtained and/or nodal segments were cultured onto standard T17 agar medium containing Schenk and Hildebrandt (1972) macro nutrients+Murashige and Skoog (1962) micro nutrients+BAP 1.0 mg/l+IBA 0.3 mg/l+3 % (w/v) sucrose+0.8 % agar. Growth in terms of stem length, second node length, stem diameter, leaf size, number of shootlets and total number explants suitable for further multiplication were recorded at the end of six weeks after culturing. Among these, superior clones variation in terms of growth parameter were observed e.g. when average stem diameters of 10 clones were compared, some of which (clone 193 and 36) were 1.1+0.1-1.2+-0.4 mm., whereas the rest were from 0.8+-0.1-0.9+-0.1 mm. Their average stem length also greatly differed from 30.7+-6.4-54.7+-11.5. Average leaf size of these 10 clones were from 4.2+-0.9-8.6+-2.1 mm. for leaf width, and from 10.8+-1.7-20.1+-5.2 mm. for leaf length. When top of cultured shootlets and nodal segments of six clones were compared, variation in terms of growth measured was also observed having the same trend in cultures of both explant origins. Generally growth and multiplication rates from nodal segments are better than from top of cultured shootlets i.e. 3.8+-1.3-6.9+-3.4 VS 1.7+-1.5-5.2+-1.9. Multiplication is generally increased when the culture were kept 2 weeks longer i.e. 8 weeks. Although quantitative growth differences were found in individual clone; all clones showed desirable traits normally present in superior clones i.e. straightness and low branching capacity. In vitro growth of teak cultured on a standard medium may be considered as a potential tool for teak clonal selection.