ISHS Acta Horticulturae 545: V International Protea Research Symposium
NEW CROP DEVELOPMENT IN THE PROTEACEAE |
| Authors: | M. Sedgley, M. Matthews |
| Keywords: | Dryandra, Isopogon, cut flowers, breeding system, seed germination, pistil, pollen |
| Abstract:
The Australian genera Dryandra and Isopogon are used in floriculture to a small extent, but have potential for further exploitation given appropriate research input. The structure of the pistil and pollen of a range of Dryandra and Isopogon species was investigated, to determine the relationship between the two for successful pollination. The pollen grains of Dryandra were elongated with two germination pores, whereas those of Isopogon were triangular with three pores. Dryandra species had a stigmatic groove, whereas Isopgon had a tube, which could accommodate more pollen grains. Experiments were conducted into the breeding system of two species of Dryandra, D. formosa and D. quercifolia. Both were found to show peak receptivity of the stigma at 2-6 days after flower opening. Hand pollination results at peak receptivity showed that both species had a mixed breeding system, with crossing more successful than selfing. Abortion of selfed seed was observed, and D. formosa was more self-compatible than D. quercifolia. Seed germination was investigated for a number of species of both genera, and the optimum was found to be 15°C. Germination did not occur at 5 and 35°C, but some species responded to a wider range of temperatures than others. Seedling emergence was investigated under glasshouse conditions of 28°C maximum and 20°C minimum temperature, but the germination rate and percentage were both lower than at 15°C. The results provide information on how to develop these species for floriculture via plant breeding. | |
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