Effects of zeatin and kinetin on in vitro regeneration of Hevea brasiliensis RRIM 2025

Efforts were undertaken to improve regeneration of Hevea brasiliensis clone RRIM 2025 plants via in vitro culture technology. A total of 12,938 tapetum (anther walls) explants were cultured. Somatic embryogenesis (SEm) were induced on nine different embryogenesis induction media supplemented with zeatin or kinetin, in three separate experiments performed for three consecutive flowering seasons. Callogenesis was significant with the highest mean value at circa 97%. Although SEm and plantlets regeneration were achieved, the results were not significant. SEm formations were slightly insignificantly higher with RD1 supplemented with zeatin at 0.5 mg/L (9.99%) and RD1-E1 enriched with 0.3 mg/L kinetin (11.1%). A high variance of results discerned at embryogenesis and plantlets regeneration stages could be attributed to origin of explant and its susceptibility to variations in climatic conditions. In total, 42 plantlets were obtained and these results would prove invaluable for further improvement of in vitro propagation of RRIM 2025