CLONAL VARIABILITY IN TENSION WOOD FORMATION IN THE JUVENILE AND MATURE GROWTH PHASES OF Hevea brasiliensis

摘要

The distribution pattern and proportion of tension wood in the juvenile and mature growth phase of Hevea brasiliensis with special reference to clonal variability was studied. In both juvenile and mature phases, compact arcs and discrete groups of tension wood fibers were observed in the central and peripheral zones of the trunk. The proportion of tension wood in juvenile wood was the highest in Tjir 1 and the lowest in Gl 1 and the variation was highly significant. In mature trees the proportion oftension wood increased from base to top of the tree trunk in Tjir 1, RRIM 600 and RRII 105 whereas in GT 1 the highest proportion was observed in the middle part of the tree trunk. In mature trees of 4 clones studied viz. Tjir 1, GT 1, RRIM 600 and RRII105 the proportion of tension wood was the highest in RRII 105 and the lowest in GT 1. The triggering factors responsible for tension wood formation is more active in the juvenile than the mature growth phase in H. brasiliensis.