This study has developed the first formal breeding objective for the Australian tea tree plantation industry. Significant gains in profitability of Australian tea tree (Melaleuca alternifolia) could be made through selection for biomass and oil yield, while maintaining oil quality at acceptable levels. Economic values or weights (EWs), for breedingobjective traits were estimated based on a bioeconomic model of a typical production system in Australia. Sensitivity of EWs to the productionsystem parameters was analysed by what-if scenarios. Selection indices and genetic responses were derived and sensitivity of selection index coefficients to variation in EWs and genetic parameters were analysed by Monte Carlo simulation. The EW for average leaf biomass (LB) and oil content (OC) had the net present value of AU$29.53/kg and AU$2059 per mg/g, respectively. Among the production system parameters studied, discount rate and oil price had large impact on the two EWs, while operating costs changed the EW of LB but did not affect the that of OC. Using optimal selection index, positive expected responses in objective traits LB (36.2 kg/ha/year), OC (4.64 mg/g), and in all selection traits (i.e. juvenile OC, height, leafiness, and 1,8-cineole) were obtained except for terpinen-4-ol, at a 10% selection intensity (i = 1.76). Use of restricted selection index resulted in zero change in either 1,8-cineole or terpinen-4-ol content, but also in an opportunity cost especially in OC. The most important factor affecting the sensitivity of the selection index was the EW for OC.
Kulim (Scorodocarpus borneensis Becc.) is one of Indonesian wood species with high economic value. Kulim wood is widely used for house construction, bridges and shipbuilding, while its fruit is used for cooking for its garlicy fragrance. Unfortunately, this species is currently rare in the wild due to habitat disturbance. Re-planting efforts require good quality seeds which can be collected from designated seed sources. The aim of this study was to identify the potential of Kulim stand in the arboretum of PT. Arara Abadi, Riau which covers 26.2 ha. Data collected from the site include tree height, diameter, geographic position as well as stand conditions. Total of 152 individual trees (121 trees, 23 poles, 5 saplings and 2 seedlings) were found in the area of study. The area is accessible, relatively safe from interference and well managed. The quality of the stands is quite good with no significant attack from pests or diseases. Fruits, seedlings and saplings were also found in the forest floor. The stand is therefore appropriate to be designated as Identified Seed Stand of Kulim based on the criteria of regulation concerning implementation of forest seeds. This stand can also be reserved as an insitu conservation area of Kulim.
In this study, modification of tissue culture sterilization techniques using methylisothiazolinone bocide (MB) in liquid and solid medium was used to evaluate the acquisition of axenic Casuarina equisetifolia culture in vitro with natureexplant sources. One experimental unit had 12treatment combinations with 20replications of explants in each treatment. Acquisition of the best axenic culture of C. equisetifolia after 30 days of incubation was in a sterilization combination for 3 days shaking out in liquid WPM medium with 8 mg/l MBand in solid WPM medium with 6 mg/l MB.C. equisetifoliashowsa good growth response in WPM medium without the addition of exogenous growth hormone. The first indication of axillary shoot explants were elongation response within 15 days of culture initiation. Shoot tips changed in color from dark green to a more obvious transparent green and the internode sections became swollen and barrel-shaped. Single shoot formation from axillary buds at basal nodes and sprouted lateral buds were visible within 30 days. The 90%of shoot formation in the axenic culture of Casuarina equisetifolia werefrom lateral buds.
Australian tea tree (Melaleuca alternifolia) is a woody plant that produces an essential oil with antiseptic, anti-bacterial, anti-fungal, and antiinflammatory properties and is widely formulated into many products. Yield and financial analyses were done to compare the viability of replanting 20 ha tea tree plantations using elite clones and improved seedlings over a 15 year time frame were carried out. Four plantation options were modelled: (1) plantations established using genetically improved seedlings (ATTIA 2B) planted at a stocking of 33,333 plants/ha and (2) 16,667 plants/ha, (3) plantations established using the best three selected clones planted at a stocking of 33,333 plants/ha and (4) 16,667 plants/ha. Financial analysis showed that, at an oil price of $45/kg (as at Sep 2008), replacement plantations of either elite clones or improved seedlings are both highly profitable irrespective of the stocking employed. The Net Present Values per hectare at 7% discount rate was $107,824, $63,640, $163,162 and $104,055 for plantation options 1, 2, 3 and 4, respectively. Plantation option 3 was predicted to give the greatest profit at any of the oil prices tested, followed by plantation option 1, 4 and 2. The breakeven prices for tea tree oil production, using the production parameters in this model were $11.81/kg, $15.19/kg, $10.72/kg and $12.96/kg for plantation options 1, 2, 3 and 4 respectively.
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