Abstract:
The effect of the origin of explants from different zones of the source plants on in vitro axillary bud growth
in rubber (Hevea brasiliensis Muell Arg.) was investigated. Both juvenile (seedling) and mature (clonal)
plants were used. Explants were harvested from shoots originated at different heights from 10 cm up to 180
cm. Mean lengths of the axillary shoots produced by the first nodal explants harvested from juvenile origin
plants cut at 10,60 and 120 cm were 38.2,37.1 and 11.5 cm respectively at 10 weeks of culture. However, with
clonal materials, mean lengths of 25 and 7.5 cm were obtained after 9 weeks of culture for the first nodal
explants produced from plants cut at 30 and 180 cm heights. The results confirmed that juvenile materials
are more responsive to in vitro culture. It was also revealed that the juvenile characters are more in the
tissues close to the root system in mature rubber plants. Better understanding and manipulation of explants
seems to be important for developing a successful protocol for micropropagation of clonal Hevea of mature
origin.
