Growth and flowering response of Bunga Kantan {Etlingera elatior (Jack) R.M. Smith) to the application of plant growth regulators / Tsan Fui Ying, Sam Yen Yen and Zainuri Mohd. Salleh

The Zingiberaceae family has many underuntilised ginger species with great potential to be introduced as ornamental and hortucultural plants. One of them is Etlingera elatior or more commonly known as bunga kantan or 'Torch ginger'. Preliminary studies conducted at Louisiana State University indicated that the application of triazoles inhibited the vegetative growth but increase the flowering of other ginger species, i.e. Curcuma and Kaempferia species. However, not much scientific studies have been done on E. elatior as an ornamental plant. Intensive research is urgently needed as this species is gaining popularity as cut flower. This study was aimed to determine the effects of the application of plant growth regulators on the vegetative growth and flowering of E. elatior var. pink. Paclobutrazol and uniconazole were the plant growth regulators applied in this study. These plant growth regulators are gebberellin biosynthesis inhibitors that result in reduced cell elongation and vegetative growth and hence, allow more energy to be utilized for flowering. This study was carried out at a site beside the Majlis Bandaray Shah Alam (MBSA) Nursery without any charge. The experimental site was first cleared by slashing the shrubs followed by the construction of drains and preparation of the planting beds by using a backhoe. A total of 70 planting beds of lxlm were prepared. The distance between beds was 0.5m. Then, 10 soil samples were collected randomly for soil analysis. After planting the rhizomes, "Aquastore" was applied to reduce water shortage problem during drought. Oil palm fronds were used to provide temporary shade for the first 3 months after planting. Application of fertilizer, pest and disease control were carried out for optimum growth of the plants. Based on some preliminary studies, the plants were soil applied with 0, 2, 4, 6 and 8 g/L paclobutrazol at six month-after planting in the first experiment. The plants in the second experiment were soil applied with 0, 25, 50, 75 and 100 gm/L uniconazole. There were two application frequencies, i.e. single application at six month-after planting and two applications at six and nine month-after planting respectively. The experimental site was a sandy clay loam site that had low organic matters and nutrients. The soil was also rather acidic. Under such soil condition, the height, leaf area index, tiller number and leaf number per tiller length of E. elatior were inhibited after 3-4 months following the application of paclobutrazol. Application of this compound at higher rates of 6 and 8 g/L resulted in compacted appearance of the plants and shining green leaves. The leaves developed, however, showed crinkled appearance. The experiment was terminated as many plants were partially buried after the heavy downpour in January 2007. Hence, the study on the inflorescence induction by means of application of paclobutrazol was not carried out. Uniconazole, on the other hand, was not effective to inhibit the vegetative growth of E. elatior. However, treatment with this plant growth regulator at rates of 50mg/L (twice) and 75mg/L (once or twice) could induce inflorescence development in this species. There was no impair in the appearance of the inflorescence following treatment with this triazole compound.