PRELIMINARY STUDY ON MICROPROPAGATION OF LEMON-SCENTED EUCALYPTUS - Corymbia citriodora

Abstract

Corymbia citriodora, commonly known as Lemon-scented Eucalyptus, is a valuable tree species with high economic potential due to its essential oils and fast-growing nature. This study presents a preliminary investigation into the clonal propagation of C. citriodora using in vitro tissue culture techniques. Semi-mature shoot segments collected from 1.5 - 2 year-old mother plants were surface-sterilized and cultured on modified MS media supplemented with plant growth regulators. Treatment with 0.1% HgCl₂ for 4 minutes provided the most effective sterilization, yielding 67.78% clean explants, low contamination and mortality rates (14.44% and 15.56%), and an effective shoot induction rate of 27.78%. In contrast, treatment with 5% Javel for 6 minutes resulted in a lower effective shoot induction rate of only 25.56%. The best shoot regeneration of C. citriodora was observed in the MS* medium. The optimal shoot multiplication medium for C. citriodora was MS* supplemented with 0.5 mg/l BAP + 0.5 mg/l NAA + 30 g/l sucrose + 5.5 g/l agar, resulting in a shoot multiplication factor of 2.45 and an average shoot length of 2.98 cm. The most suitable rooting medium for C. citriodora was 1/2 MS* supplemented with 2 mg/l IBA + 0.75 mg/l ABT + 30 g/l sucrose + 5.5 g/l agar, which achieved a rooting rate of 84.44%, with an average of 3.15 roots per shoot and an average root length of 1.62 cm. These findings demonstrate the feasibility of micropropagation for C. citriodora, providing a potential foundation for large-scale propagation and conservation of elite genotypes.