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Development and potential of holdfast phalaris

R.N. Oram and H.E. Schroeder

CSIRO Division of Plant Industry, GPO Box 1600, Canberra ACT 2601

In 1971 the second author discovered one plant in Australian phalaris which held most of the ripe seed in the panicles. Rachillae were not pinched off during seed maturation. Seed retention depends on recessive alleles at four loci.


To generate a genetically diverse population of seed-retaining plants, three rounds of outcrossing and backcrossing were conducted (1). In each round, retainers were outcrossed to the progenitors of Sirosa and Sirolan, or to 15 Mediterranean ecotypes, and the F1s backcrossed to the retainers from the previous cycle. The resulting 59 retaining plants were polycrossed. Their half-sib progeny were tested both for yield and persistence in replicated four-row plots of 5 m2 area at Temora and Canberra in 1983-85, and for seed yield, retention, flowering time and growth habit as spaced plants in Canberra. Two hundred and nineteen plants were selected, cloned and tested for root growth in nutrient solution containing 6 mg/L aluminium at pH 4.1. Fifty-three plants with the greatest Al-tolerance were polycrossed and the three-year selection cycle was repeated, using a 10 mg/L Al challenge. The resultant 45 plants were clonally propagated and grown in isolation to produce Fe-breeder's seed of the new cultivar, Holdfast.

Results and discussion

Table 1. Comparisons of phalaris cultivars.

Holdfast is higher yielding than Australian as a seedling and as spaced plants during winter of the first year, but slightly lower yielding than Sirosa. Under grazing, the herbage available in autumn shows smaller differences. Holdfast resembles Sirosa in height, and tiller density. Holdfast is late flowering, and has a lower tryptamine alkaloid content than Australian and Sirosa. Holdfast has been more productive than Sirosa on an acid soil near Canberra, but not near Swanpool, Victoria (Oram, unpublished data). Seed price should be lower for Holdfast than for non-retaining cultivars because Holdfast yields 50-100% more seed (S. Martyn, pers. comm., 1989). Therefore it is expected that Sirosa will be gradually replaced by Holdfast in the main phalaris belt.


This project was funded by the Wool Research and Development Corporation.


Oram, R.N. and Schroder, H.E. 1984. Proc. Seeds Res. Conf., Lawes, pp. 188-191.

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