Publication Date

1985

Location

Kyoto Japan

Description

Subterranean clover cultivars are being increasingly found in mixed strain sowings in Australia. Mixed sowing or oversowing may be done deliberately to overcome the problem of the high oestrogen content of some older strains in established pastures. However, some of the existing cultivars have aggressive growth characteristics, and may not be easy to replace. Identification of competitive characteristics and competition between strains needs examination. Three cultivars (Larisa, Yarloop and Woogenellup) were grown alone and in mixtures at three temperature levels and either at field capacity or at below 50% of field capacity in glasshouse trials. Larisa appeared to be suppressed by Yarloop and Woogenellup at intermediate temperatures, but was not so affected at lower temperatures. Both Larisa and Woogenellup produced greater root mass and Yarloop less under competition. The effects of competition between cultivars was assessed further by fitting temperature/moisture quadratic response curves. Changes in both the explained variance and in the regression coefficients (temperature for optimum response) were used to assess the effects of competition. I:he equations derived can be used to quantify the differntial response in topweight, rootmass, height, leaf number and other characteristics to temperature for individual cultivars alone and in mixtures or for differences between cultivars. It is proposed that with further work it may be possible to map regions in terms of the degree of potential intercultivar competition.

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Growth Characteristics of Subterranean Clover Cultivars in Mixtures at Varying Temperature and Moisture Levels

Kyoto Japan

Subterranean clover cultivars are being increasingly found in mixed strain sowings in Australia. Mixed sowing or oversowing may be done deliberately to overcome the problem of the high oestrogen content of some older strains in established pastures. However, some of the existing cultivars have aggressive growth characteristics, and may not be easy to replace. Identification of competitive characteristics and competition between strains needs examination. Three cultivars (Larisa, Yarloop and Woogenellup) were grown alone and in mixtures at three temperature levels and either at field capacity or at below 50% of field capacity in glasshouse trials. Larisa appeared to be suppressed by Yarloop and Woogenellup at intermediate temperatures, but was not so affected at lower temperatures. Both Larisa and Woogenellup produced greater root mass and Yarloop less under competition. The effects of competition between cultivars was assessed further by fitting temperature/moisture quadratic response curves. Changes in both the explained variance and in the regression coefficients (temperature for optimum response) were used to assess the effects of competition. I:he equations derived can be used to quantify the differntial response in topweight, rootmass, height, leaf number and other characteristics to temperature for individual cultivars alone and in mixtures or for differences between cultivars. It is proposed that with further work it may be possible to map regions in terms of the degree of potential intercultivar competition.