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Competition studies in diploid and tetraploid varieties of Lolium perenne: 1. The influence of density and proportion of sowing

Published online by Cambridge University Press:  27 March 2009

J. Norrington-Davies  and
J. H. Harries
J. Norrington-Davies
Affiliation:
Department of Agricultural Botany, University College of Wales, Aberystwyth
J. H. Harries
Affiliation:
Department of Agricultural Botany, University College of Wales, Aberystwyth
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Summary

Two varieties of Lolium perenne, the diploid Hora and the tetraploid Terhoy were sown either as a pure stand or as a binary mixture on to the surface of multipots filled with a standard John Innes compost. Density of sowing was varied over the range of 16, 24, 36, 50 and 100 seeds/pot. There were four replicates. The pattern of germination was followed over a period of 14 days when it was found that (i) the varieties did not differ in their germination when grown alone, but in mixtures the diploid was slower to germinate than the tetraploid, (ii) as the density of sowing per pot was increased, the mean germination time (MGT) was increased, and (iii) the final germination of both verities decreased with increasing density.

In a second experiment the same procedures were followed as before but seed of each variety was sown either as a pure stand or in a mixture of varying proportion as follows: 100:0, 75:25, 50:50, 25:75, 0:100.

The results showed that (i) the diploid had the fastest MGT whilst the mixture values showed no significant variation, and (ii) the final germination percentage of the diploid decreased relative to its pure stand value as its proportion in mixtures decreased, whilst the tetraploid under the same circumstances increased relative to its pure stand value.

It is suggested that differences such as those found could be explained by the presence of germination inhibitors in the seed coats of the two ryegrass varieties.

Type
Research Article
Information
The Journal of Agricultural Science , Volume 88 , Issue 2 , April 1977 , pp. 405 - 410
Copyright
Copyright © Cambridge University Press 1977

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