Kenaf (Hibiscus cannabinus L.), is a potential alternative of natural wood fibers for biocomposite and pulp and paper industry. However, the average fiber length of kenaf is usually shorter than the critical length to be used for high quality biocomposite materials. Increasing fiber length and quality can diversify its application in fiber based industries. Gibberellic acid (GA3) is an important plant growth regulator that is actively involved in cell elongation and other important physiological functions in plant growth, development and flowering. To investigate the effects of gibberellin on growth, morphology, and fiber quality, some selected cultivars of kenaf plants were treated with aqueous solution of varying concentrations of GA3. The effects on vegetative and reproductive growth were evaluated weekly for sixteen consecutive weeks and fiber morphology after harvesting at 18th week. Gibberellin treatment significantly reduced the vegetative growth in terms of stem diameter, leaf number, and leaf size but stimulated fiber elongation, resulted in a tall and slender plant with curled leaves. Gibberellin treatment also impaired reproductive growth by inhibiting floral initiation and development in all treated plants whereas the control plants were in its seed harvesting stage. This study provided novel insights into the effects of GA3 in regulating vegetative and reproductive growth of kenaf as well as improving its fiber properties.

The effects of 6-Benzylaminopurine (BA), different basal medium, sucrose concentration and gelling agent were investigated for shoot induction and multiplication of Acacia auriculiformis. Nodal explants derived from 5-month-old seedlings yielded the highest shoot multiplication rate in Murashige and Skoog medium (MS) with 0.44 µM BA, 30 g/L sucrose and 2 g/L Gelrite. The highest mean number of shoots (10) and mean length of shoots (5.07mm) were also obtained in this medium. Qualitative observation of the shoots cultured in 0.44 µM BA were greener and vigorous in growth as compared to shoots cultured on higher concentrations of BA (22.2 µM). MS medium produced a significantly higher number of shoots (18) compared to Woody Plant Medium (WPM) (11) and B5 medium (10). Media solidified with different gelling agents also produced a significantly different number of shoots with 2 g/L Gelrite produced the highest number of shoots (23). The highest percentage of shoots rooted was found in the MS medium without any growth regulators (40.0%) followed by medium supplemented with Indole-3-butyric acid (IBA) at 9.84 µM and the combination of 9.84 µM IBA with 5.37 µM α-naphthalene acetic acid (NAA) (33.3%). MS medium without any plant growth regulators produced the highest mean root length (84.33mm), whereas medium supplemented with 9.84 µM IBA produced the highest mean number of roots per shoot (4.33). Out planting of in vitro rooted shoots in shredded coconut husk as the substrate gave the highest percentage of survival (90%) during acclimatization in the greenhouse.

Asexual propagation techniques for producing good quality germplasm for breeding and dissemination purposes have proven difficult for acacia species comprised of mature planting material. The study was conducted to study the effect of rejuvenation on the rooting ability of mature cuttings. Shoots were induced from the lower branch by cutting a part of the mature branch of the crown and leaving it horizontally on the propagation bench under the misting system. Shoots were harvested and further used as stem cuttings to evaluate their rooting ability through the application of rooting hormone. The rooting ability of the cuttings is highly variable among species. The percentage of stem sections producing juvenile shoots was similar for Acacia mangium Willd. (88%) and Acacia auriculiformis A.Cunn. ex Benth. (90%). Only 52% of stem sections were able to produce shoots for Acacia crassicarpa A.Cunn. ex Benth., followed by Acacia aulococarpa A.Cunn. ex Benth. with only 31%. Overall, A. auriculiformis rooted better and recorded the highest mean value for all traits tested. Hormone treatment significantly enhances the rooting ability of A. auriculiformis and A. mangium. However, A. aulococarpa and A. crassicarpa did not respond well to the treatment. Rejuvenated stem cuttings were rooted better than mature cuttings, producing the highest mean value for all traits tested in all species, with or without hormone treatment. Results indicated that it is possible to rejuvenate mature cuttings through bud break in a controlled environment.

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Medicinal plants are a vital source of new bioactive compounds due to their ecological biodiversity and varied chemical properties of each species. Phenotypic selection coupled with the evaluation of genotypes based on the chemical profile can be used for the development of a high-yielding variety. However, most of the raw material that has been used for commercial production of herbal products is mainly derived from wild sources, with little knowledge of the quality of genetic materials. Thus, three medicinal species, Chromolaena odorata (Siam weed), Andrographis paniculata (Creat), and Baeckea frutescens (False ru), were chosen based on their significant benefits to human health. These medicinal species have been traditionally used to treat various illnesses, and have been shown to possess anti-inflammatory, antimicrobial, anticancer, and antioxidant properties. This paper highlights the harvesting method and collection of accessions from natural habitats for the selection of superior genotypes. Individual plants having superior phenotypic characteristics and bioactive compounds were identified. We successfully developed appropriate propagation techniques for each species for the mass production of high-yielding planting material. The establishment of breeding activities for these medicinal plants will provide quality raw materials to support the herbal industry in increasing the value of pharmaceutical products. These efforts will also ensure the sustainable production of high-quality planting materials for the establishment of herbal plantations.