New Zealand Journal of Agricultural Research abstracts
Effect of cultivar of white clover on plant morphology during the establishment
of mixed pastures under sheep grazing
J. L. BROCK
J. C. TILBROOK
AgResearch
Grasslands Research Centre
Private Bag 11008
Palmerston North, New Zealand
Abstract The establishment of white clover from seed is
characterised by two distinct morphological growth forms, a seminal tap-rooted
stage with radiating stolon systems lasting 1-2 years, followed by a clonal
growth form. Transition of a plant from tap-rooted to clonal form occurs when
the tap root and primary stem axis die, releasing a variable number of stolon
systems as independent clonal plants. The purpose of this study was to
investigate any effect different cultivars of white clover may have on the
morphology of plants during the transition of populations from tap-rooted to
clonal growth form when establishing in mixed pastures based on either
perennial ryegrass or tall fescue. Cultivars studied ranged from small-leafed
to large-leafed cultivars in the order of Prop, Prestige, Demand, Huia,
Sustain, Le Bons, Kopu, and Aran. During the tap-rooted phase there were no
differences between cultivars in shoot growth apart from the small-leafed
cultivars (Prop, Prestige, Demand, and Huia) having a higher plant branching
order and lower partitioning to leaf than the large-leafed cultivars (Sustain,
Le Bons, Kopu, and Aran). After one year, tap-rooted plants were 4-5 times
larger than plants in the subsequently formed clonal populations. Tap root
death and fragmentation to form clonal plants commenced one year after sowing
and initially occurred at a faster rate in small-leafed than in larger-leafed
cultivars. By 15-18 months later, loss of all tap-rooted plants in all
cultivars was complete. The mean characteristics of clonal plants and
populations were similar for all cultivars, and similar to those reported in
other studies. It took two years of differential grazing management to achieve
the balance in plant DW structure reported in older pastures. The possible role
of changes in plant form in cultivar performance is discussed.
Keywords white clover cultivars; Trifolium repens;
plant structure; population structure; taproots; plant fragmentation; clonal
growth; establishing pasture; grazing management
New Zealand Journal of Agricultural Research, 2000, Vol 43: 335-343
0028-8233/00/4303-0335 $7.00/0 (c) The Royal Society of New Zealand
2000
PDF file of entire paper: medium quality (727K); (scanned from paper original: notes about this process)
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