Establishment of micropropagation technique for hevea brasiliensis / Aicah Patuhai

Micropropagation offers many benefits to Hevea tree as this technique is capable to produce plant without seasonal interruption. In present research, the effect of different types of media and plant growth regulators on callus induction and shoot initiation from different explants of Hevea brasiliensis were investigated. The optimization of sterilization technique was conducted to reduce contamination and to obtain the most suitable media for callus induction and shoot regeneration on different explants of three Hevea clones; RRIM 3001, RRIM 2025 and PB 350. Callus were induced from the leaf and stem explants while shoot was initiated from the axillary buds. Leaf, stem and axillary bud explants were cultured on five different treatments which consist of three types of media (MS, WPM, DKW) supplemented with various combinations and concentrations of plant growth regulator namely a-naphtalene acetic acid (NAA), benzylaminopurine (BA), 2,4-dinitrophenylhydrazine (2,4-D), zeatin, sucrose and coconut water. The experiment was carried out at the laboratory of Genetic Transformation and Tissue Culture Programme (GTTC) Rubber Research Institute Malaysia, Malaysian Rubber Board Sungai Buloh, Selangor. Based on the results obtained, Procedure 3 was found the optimum sterilization procedure for all clones whereby increase in duration and concentration of sterilization solution help in removing contamination. It was also interesting to observe that Treatment 3, MS media supplemented with 0.5 mg L"1 BA, 0.5 mg L"1 2,4-D, 0.5 mg L"1 Zeatin, 7% sucrose and 10% coconut water, gave significant effect on callus induction in both leaf and stem explants for all types of clones. Among the treatments, the highest callus diameter was observed in clone RRIM 3001 (stem : 2.34 cm, leaf : 1.95 cm), the highest plant survival rate was observed in clone RRIM 2025 (stem : 82%; leaf : 86%), and the fastest callus induction was observed in clone RRIM 2025 (stem : 9 day; leaf : 10 day). Different characteristics of callus such as friable, compact and yellowish were observed in all treatments. Meanwhile, Treatment 5 (DKW media + 0.5 mg L"1 BA, 0.1 mg L"1 NAA and 7% sucrose) was recorded as the best media for shoot induction. Among the treatments, the highest plant survival rate was observed in clone RRIM 3001 (42%) and the earliest shoot induction was observed on clone RRIM 3001 (28.8 day). For future study, investigation on the ability to produce root and acclimatization need to be conducted to assess the overall potential of in vitro Hevea seedling.