Longer defoliation interval ensures expression of the ‘high sugar’ trait in perennial ryegrass cultivars in cool temperate Tasmania, Australia

Turner, L. R. and Donaghy, D. J. and Pembleton, K. G. and Rawnsley, R. P. (2015) Longer defoliation interval ensures expression of the ‘high sugar’ trait in perennial ryegrass cultivars in cool temperate Tasmania, Australia. Journal of Agricultural Science, 153 (6). pp. 995-1005. ISSN 0021-8596

Abstract

Perennial ryegrass (Lolium perenne L.) cultivars have been developed to express higher levels of leaf water-soluble carbohydrates (WSC), but expression of this ‘high sugar’ trait varies between environments and is likely to be further influenced by the extent of plant re-growth. The herbage WSC concentration and the ratio of WSC to crude protein (WSC: CP) in high sugar cultivars AberMagic and SF Joule were therefore compared with a control cultivar, Arrow, under cool temperate Tasmanian conditions and two defoliation interval treatments. The irrigated cultivars were subjected to defoliation at either the 1·5-leaf or 3-leaf stage of re-growth, and additional components of nutritive value (fibre concentrations and metabolizable energy content) and dry matter (DM) yields were measured throughout a 12-month period (March 2011 to March 2012). The high sugar trait was consistently expressed in AberMagic, which under both the 1·5-leaf and 3-leaf stages defoliation intervals, displayed the highest WSC concentration (mean 194 and 247 mg/g DM, respectively, compared with 153 and 178 mg/g DMfor Arrow) and highest WSC:CP ratio (mean 0·74 and 1·29, respectively, compared with 0·58 and 0·85 for Arrow). Defoliation at the 3-leaf stage of regrowth ensured greater expression of the high sugar trait in both AberMagic and SF Joule, as measured by the increase in WSC concentration and WSC:CP ratio as a result of increasing defoliation interval. The strength and consistency of trait expression in AberMagic under the 3-leaf stage defoliation interval warrants further research to investigate its effect on rumen nitrogen (N) partitioning and milk production in this environment.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Access to published version in accordance with the copyright policy of the publisher.
Faculty / Department / School: Current - Institute for Agriculture and the Environment
Date Deposited: 28 Jul 2016 04:28
Last Modified: 04 Jun 2018 05:18
Uncontrolled Keywords: Lolium perenne
Fields of Research : 07 Agricultural and Veterinary Sciences > 0701 Agriculture, Land and Farm Management > 070199 Agriculture, Land and Farm Management not elsewhere classified
05 Environmental Sciences > 0503 Soil Sciences > 050399 Soil Sciences not elsewhere classified
06 Biological Sciences > 0607 Plant Biology > 060799 Plant Biology not elsewhere classified
Socio-Economic Objective: D Environment > 96 Environment > 9614 Soils > 961402 Farmland, Arable Cropland and Permanent Cropland Soils
Identification Number or DOI: 10.1017/S0021859614000628
URI: http://eprints.usq.edu.au/id/eprint/29535

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