Progress report on the grant:
Aileen Reid, Development Officer, Department of Agriculture
Eric Bunn, Research Officer, Kings Park and Botanic Gardens. 11/10/95
Crop Establishment
This part of the project looks at the effect of planting time (April, July, October and January) and the type of planting material (50 cm tubes, 100 cm tubes and peat pots) on establishment. Three of the four plantings have been completed. All the plants have been mulched with Casuarina needles and a small amount of low phosphorus Osmocote® was applied to each planting, one month after planting. Fosject® (phosphorous acid) was applied at 5 mL/L as a soil drench at planting as a precaution against Pythium. Irrigation is being applied through 4L/hour drippers for 30 minutes each day.
The first planting in April showed no growth until the August assessment. The plants in the second (July) planting were already showing some signs of growth when planted and have since continued to grow. Most of the plants assessed in September had two new leaves at least 30 40 mm long regardless of the time of planting
There were no significant plant losses until the August September period. The losses have all been in the 50 cm tubes or the peat pots. Most of these losses are believed to be from snail damage. Two types of snails are prevalent on the research station and although baits and sprays have been applied on a regular basis, some damage is present. The smaller plants are much less able to resist these attacks.
Table 1. Summary of plant growth and establishment to 10 September 1995.
|
Mean change in |
Mean change in leaf number (mm) |
Plant survival |
||
| April planting | ||||
| 100 cm.
tubes |
4 |
3.0 |
30 |
|
| 50 cm tubes |
6.9 |
0.7 |
30 |
|
| Peat pots |
31.6 |
2.5 |
28 |
|
| July
planting |
||||
| 100 cm.
tubes |
(20.1) |
0.1 |
28 |
|
| 50 cm tubes |
15.6 |
(3.2) |
14 |
|
| Peat pots |
35.4 |
(4.0) |
12 |
|
Tissue Culture
Shoot cultures have been established and proliferation of shoots is under way. Shoots are being proliferated on a half-strength MS (Murashige and Skoog, 1963) medium as described in Bunn and Dixon (1992). Shoot proliferation is similar to that obtained in Bunn and Dixon (1992), however some differences in response may be expected due to clonal differences in source material. Some rooted shoots have been produced and shoots have been established in soil mix, however shoot numbers are not yet sufficient to produce large numbers of rooted shoots
Cuttings
Approximately 70 cuttings were prepared from material harvested from field grown plants in June. Cuttings were treated with a basal application of a commercial striking solution (active ingredient 4000 ppm K-IBA). Cuttings were placed in a well drained soil mix of equal parts coarse sand, peat and perlite and kept on a warming bench (about 28ºC). Roots did not form on any cuttings after four months and all cuttings were subsequently discarded. It is possible that conditions were unsuitable to induce root induction or the cutting material was unsuitable.
Project directions for 1995/96
Successful establishment in soil is crucial to the success of Stirlingia as a commercial crop. As a means to investigate possible causes and solutions to successful establishment of S. latifolia it is intended to :
1. Continue work on vegetative propagation of Stirlingia. This is necessary to compare growth of plants from tissue culture with that of plants from normal vegetative propagation methods. Some vegetative propagation has already been carried out but for commercial use, strike rates need improvement.
Field work with Stirlingia currently being carried out has indicated some promising directions for cutting propagation of this crop. Observations of plants in the field that have been trampled by animals have shown that the stems react strongly to being in a horizontal position by shooting from each leaf axil. Presumably this is due to the removal of apical dominance. Other plants that have been submerged in sand by ants building nests around their base have produced many shoots from around the base of the plant with etiolated bases that appear ideal for cuttings. We intend to look at producing Stirlingia cuttings using a stool bed approach, either with or without laying stems horizontally.
2. Continue work on establishment methods. One planting remains and data will be collected monthly to complete this phase of the project.
Look at the effect of nutrition on the root: shoot ratio. One of the current problems with this crop. is that it is a typical resprouter species. Therefore the plant puts all its efforts into building up its root system and carbohydrate stores before it produces substantial numbers of flowering stems. Thus, from the small plantlets normally planted out in a commercial situation, significant production of flowering stems is not obtained for several years, making the economics of growing this crop less attractive. We will compare high nitrogen, high potassium and normal NPK formulations in pot trials to see if these have an effect on root:shoot ratios. It is also possible that high potassium nutrition may improve branching which would further increase production. The use of high potassium nutrient formulations is often recommended in the palm industry for this reason.
4. Compare establishment success in soil of in vitro rooted shoots, unrooted in vitro produced shoots (microcuttings) and conventional cuttings to give an indication of the suitability of different propagules for use in commercial plantings.
5. Examine and measure morphological characters of root systems derived from plants produced from tissue culture and from conventional propagation.
Other field work on bushstands of Stirlingia has identified plants which are early flowering or have bud colour. These are being put into culture and bulked up as suitable shoot material becomes available. Results from this project will identify techniques which can be used to field trial these selections on grower’s properties at a later date. The outcome will then be lines of Stirlingia which can be profitably grown for selling in bud to the fresh flower market or in fruit as a processed product to the dried flower market.