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Final report on the Australian
Flora Foundation funded project:
The Collection and Evaluation of Daisies (Tribe
Inuleae) with Horticultural Potential
Grant details Send
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K.V. Sharman1 and R. Dowling2
1 Senior Research Horticulturist Redlands Research Station, PO Box 327,
Cleveland 4163 Qld
2 Botanist Queensland Department of Primary Industries, Botany Branch,
Meiers Road, Indooroopilly 4068 Qld
Introduction
A planned field trip to western Queensland to collect seed of potential
species was aborted due to poor autumn rains and general drought conditions
during 1992. Research was therefore limited to seed obtained from commercial
seed suppliers. A major review of the Asteraceae has also been published
since the commencement of this research and as a result many name changes
have taken place. The germination requirements of twenty seven species
were evaluated at Redlands Research Station and these are listed in Table
1 along with synonyms where appropriate.
Materials and methods
Test seed was stored for a minimum of six months at room temperature prior
to treatment. Germination trials were conducted in 9 cm petri dishes lined
with two Whatman No. 1 filter papers on laboratory benches in ambient
temperature conditions. A minimum of three and maximum of six species
were evaluated in each of five germination trials. Each trial was a completely
randomised design of three germination treatments; intact seed treated
with water, scarified seed treated with water, and intact seed treated
with gibberellic acid, with two light levels (light and dark) and five
replicate petri dishes of 15 seeds, for each species evaluated. Seeds
were moistened with either 5 ml distilled water or 500 mg/1 GA3 solution.
Both solutions contained 0.2% Thiram fungicide (Amalgamated Chemicals).
Seeds were scarified by piercing the seed coat with a dissecting needle
to expose a portion of the endosperm. Seed of Chrysocephalum apiculatum
was considered too small to scarify without damaging the embryo. This
treatment was therefore omitted for this species. Dark treated seeds were
covered with alfoil while light treatments were exposed to a combination
of fluorescent and natural light for 10 to 12 hours daily. Germinated
seeds were counted at day 15 in dark treatments and every three days for
30 days in light treatments. Seed was considered to have germinated once
the radicle had emerged. At the end of the assessment period ungerminated
seeds were dissected and those which contained partially formed or no
embryos were scored as nonviable. Germination was then recorded as percent
viable seed. Results were statistically analysed using arcsine transformed
data.
Results and discussion
A summary of the results and recommendations for seed treatment is presented
in Table 1. Some species such as
Leucochrysum fitzgibbonii and Rhodanthe moschata were
still dormant up to nine months after seed collection while Rhodanthe
chloroccphala subsp. rosea and Rhodanthe humboldtiana
were not dormant after six months storage at room temperature.
Gibberellic acid was beneficial as a pre-germination treatment for Chrysocephalum
podolepidium, Leucochrysum fitzgibbonii, Leucochrysum
molle, Myriocephalus stuartii, Podolepis jaceoides,
Rhodanthe moschata, Rhodanthe polygalifolia and Rhodanthe
stricta.
Scarification was necessary for the germination of dormant seed of Lawrencella
rosea and promoted germination in Leucochrysum stipitatum,
Rhodanthe chlorocephala subsp. chlorocephala and Rhodanthe
manglesii.
Light was not an obligatory requirement for germination in any of the
species evaluated however it did have a promotory influence on germination
of Brachyscome iberidifolia, Chrysocephalum apiculatum,
Hyalosperma glutinosum subsp. venustum, Leucochrysum
fitzgibbonii, Leucochrysum stipitatum, Rhodanthe stricta
and Watzia acuminata. It is therefore suggested that these species
be sown on the soil surface.
Further research
The support received from the AFF during 1991 was instigative in the securing
of further funds from the Horticultural Research and Development Corporation.
The new research 'Year-round Production of Australian Daisies' will be
conducted over a three year period (1992-1993) and aims to determine the
flowering requirements of native daisies. Further research into the germination
and vegetative propagation of native daisies will continue within the
new grant. An exciting development from this new work has been the discovery
that high temperature storage may break dormancy of many daisies and we
are looking into this in more detail.
Publication and extension
Sharman K.V. (1992) Flowering daisies - in July. Ornamentals Update 7:
4.
Sharman K.V. (1992) Research to put native daisies on desks. Prime News
5: 3.
Sharman K.V. (1992) Research focus on flowers. The Redland Times 9 Sept.
Sharman K.V. (1992) Native paper daisies have future as fresh flowers.
Flower Link
10(12):23.
Sharman K.V. (1992) Year - round production of flowering daisies. Seminar
presented at
Redlands Research Station 2 Dec.
Sharman K.V. (1992) Front Cover Australian Horticulture, profile of author
and research
activities. 90(12) 44.
Sharman K.V. (1993) Seed Germination and Dormancy of Australian Daisies
(Asteraceae) Scientia Horticulturae (in preparation).
Budget summary
Item
$
Seed from seed suppliers 500
Petri dishes
164
Dissecting equipment
110
Gibberellic acid
260
Miscellaneous consumables 100
Casual labour
866
TOTAL
2000
Note that considerably more casual labour was supplied from funds obtained
from other
granting sources including Consolidate Revenue of the Department of Primary
Industries
and the Horticultural Research and Development Corporation, as part of
the recently
funded daisy project.
Acknowledgments
The assistance of the Australian Daisy Study Group is gratefully acknowledged.
The
enthusiasm of the group and donations of seed from keen daisy lovers have
helped to
extend the project and urge us on to greater achievements.
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