New Zealand Journal of Agricultural Research abstracts
Morphogenetic adaptation to defoliation and soil fertility in perennial
ryegrass (Lolium perenne)
L. HAZARD
INRA
Station d'Amélioration des Plantes Fourragères
86600 Lusignan, France
Present address: INRA, Centre de Recherches de Toulouse, Auzeville B.P.27,
31326 Castanet-Tolosan Cedex, France
D. J. BARKER*
H. S. EASTON+
AgResearch
Grasslands Research Centre
Private Bag 11008
Palmerston North, New Zealand
*Present address: Dept of Horticulture and Crop Sciences, The Ohio State
University, Columbus, Ohio 43210, USA.
Abstract Morphogenetic adaptation, plasticity, and mortality
of four perennial ryegrass populations, representing different selection
histories, were compared in response to soil fertility and to defoliation
severity. In a second experiment, morphogenetic adaptation and plasticity in
response to defoliation frequency were studied in two divergent
sub-populations. Genetic variability was found between ryegrass populations for
leaf appearance and elongation rates, leaf size, and tiller number. All
populations exhibited plasticity in response to defoliation severity and soil
fertility. There was no genetic variation for plasticity, the morphological
response to the environment. Morphogenetic differences between populations
remained constant across environments and resulted in differential mortality
under the most severe defoliation. Both leaf length and rate of leaf appearance
were positively correlated with greater mortality. The ryegrass ideotype for
hill country is a compromise between yield and persistence.
Keywords Lolium perenne; hill country; leaf growth;
plasticity; mortality; tiller density
New Zealand Journal of Agricultural Research, 2001, Vol. 44: 1-12
0028-8233/01/4401-0001 $7.00/0 (c) The Royal Society of New Zealand
2001
PDF file of entire paper: medium quality (892K); (scanned from paper original: notes about this process)
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