New Zealand Journal of Agricultural Research abstracts
Flowering propensity of two New Zealand perennial ryegrass cultivars
originating from different ecotypes
I. Bahmani
E. R. Thom*
Dexcel
Private Bag 3221
Hamilton, New Zealand
* author for correspondence
C. Matthew
Institute for Natural Resources
Massey University
Private Bag 11 222
Palmerston North, New Zealand
G. Lemaire
Institut National de la Recherche Agronomique
Unité d’Ecophysiologie des Plantes Fourragères
F-86600 Lusignan, France
Abstract Tiller turnover at flowering is an integral
component of the perennation strategy in many temperate grasses. While vernalisation
and daylength requirements for flowering, and cultivar flowering date characteristics
are well known, there is little information on the effects of other factors,
such as N fertiliser and grazing intensity, on flowering behaviour. We compared
tiller dynamics of early flowering, endophyte-free, perennial ryegrass cultivars
(‘Ellett’ and ‘Grasslands Ruanui’) under two N fertiliser and irrigation
levels, and dairy cow grazing. In the first flowering period after sowing
(October 1996-January 1997), ‘Ellett’ ryegrass averaged 19.5% reproductive
tillers in the total tiller population, while ‘Grasslands Ruanui’ ryegrass
averaged 13.0%. In the second season (September 1997-January 1998), 17.1%
of ‘Ellett’ tillers were reproductive, compared with only 7.8% for ‘Grasslands
Ruanui’. There was a cultivar ´ N interaction in summer 1997/98, with
N increasing the percentage of reproductive tillers in ‘Ellett’, but decreasing
them in ‘Grasslands Ruanui’. The irrigation treatment did not affect flowering
behaviour. In another study, lax grazing of endophyte-infected ‘Ellett’ ryegrass
resulted in 7% of total tillers flowering compared with 34% under hard grazing.
The importance of considering the effects of latitude on flowering behaviour
is discussed.
Keywords ‘Ellett’ ryegrass; ‘Grasslands Ruanui’ ryegrass;
Lolium perenne; reproductive tillers; vegetative tillers; grazing;
latitude; nitrogen
A01037 Received 12 November 2001; accepted 10 May 2002; published 30 September
2002
New Zealand Journal of Agricultural Research, 2002, Vol. 45: 129-137
0028-8233/02/4503-0129 $7.00/0 © The Royal Society of New Zealand
2002
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