Tissue culture of rubber: past, present and future prospects

In rubber, the current propagation method of grafting on to unselected seedlings, maintains intraclonal heterogeneity for vigour and productivity and hence a great improvement may be expected by using micropropagation in vitro. Micropropagation with nodal and shoot tip explants derived from seedlings are possible as with mature clonal explants. The major problem in using clonal material from mature trees of Hevea is the failure to produce an adequate tap root system necessary for tree stability, and the poor response to culture conditions. The latter problem has been over come to a significant level by in vitro micrografting. Recently, there has been an increasing interest in the induction of somatic embryogenesis in Hevea using different explants, media compositions and conditions, especially for use in genetic transformation studies. Successful somatic embryo formation and plant regeneration have been reported by a few researchers in different countries using limited genotypes of Hevea. Attempts to induce somatic embryos from high yielding Sri Lankan clones have not been successful until the late 1990s. The frequency of somatic embryo induction was found to be very low and non-synchronous, its germination remained very difficult and thus Hevea embryogenic system needed further investigation. There is no large scale commercial application of tissue culture techniques for mass propagation of clonal Hevea as yet, either by microcuttings or by somatic embryogenesis.  However, there is sufficient progress at research level to suggest that tissue culture of Hevea can and should be further developed. Key words: Hevea brasiliensis , micropropagation, microcuttings, somatic embryogenesis doi: 10.4038/cjsbs.v36i2.486 Cey. J. Sci. (Bio. Sci.) 36 (2): 116-125, 2007