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Please use this identifier to cite or link to this item: http://hdl.handle.net/11019/54

Title: Studies into the dynamics of perennial ryegrass (Lolium perenne L.) seed mixtures
Authors: Gilliland, T.J.
Hennessy, D.
Griffith, V.
Keywords: Aggressiveness
Perennial ryegrass
Issue Date: 2011
Publisher: Teagasc (Agriculture and Food Development Authority), Ireland
Citation: Gilliland, T.J., Hennessy, D. & Griffith, V. 2011. Studies into the dynamics of perennial ryegrass (Lolium perenne L.) seed mixtures. Irish Journal of Agricultural and Food Research, 50, 99-112.
Series/Report no.: Irish Journal of Agricultural and Food Research;Volume 50: Number 1, 2011
Abstract: The dynamic interactions of four perennial ryegrass seed mixtures sold in Northern Ireland were studied under simulated grazing and conservation managements. Mixture composition was determined as changes in phosphoglucoisomerase isozyme frequencies by calculation from known isozyme frequencies of the component varieties. Mixture productivity was measured over 4 growing seasons and compared with yields predicted from those of the components in monoculture, weighted for their actual proportion in the mixture. No significant differences were found between actual yields for mixtures and their predicted yields, but when these differences were regressed against the heading date range among the varieties in each mixture, a significant relationship was observed. A wide range in heading date among the components of the mixtures was associated with increased yield stability over years and with a declining yield advantage for the mixture compared to its components grown as monocultures. In this aspect, the mixtures showed a more rapid decline under conservation management than under simulated grazing. Mixtures also had a flatter seasonal yield-production profile than their component varieties. Tetraploid components were more aggressive than diploids, though a more open-growing diploid maintained its proportion in the sward better than a dense-growing type and manipulating the sowing ratios could be used to influence final sward composition after 2 years. It was concluded that the differences in heading date range within mixtures had a significant impact on mixture dynamics, with the tetraploid component being the most aggressive.
Description: peer-reviewed
URI: http://hdl.handle.net/11019/54
ISSN: 0791-6833
Appears in Collections:Grassland Science
IJAFR volume 50, no. 1, 2011 (Special Issue)

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