New Zealand Journal of Agricultural Research abstracts
Temperature responses and nuclear DNA amounts of seven white clover populations
which differ in early spring growth rates
B. D. CAMPBELL
J. R. CARADUS
C. L. HUNT
AgResearch
Grasslands Research Centre
Private Bag 11008
Palmerston North, New Zealand
Abstract The growth of seven white clover populations
differing in morphology, geographic origin, and seasonality of growth was
measured at constant temperatures ranging from 5deg.C to 25deg.C in controlled
environment chambers. All populations showed increased growth up to a maximum
of 20-25deg.C, but there were significant shifts in the relative performance of
the populations at different temperatures. Leaf appearance rates, leaf sizes,
and stolon extension rates were all differentially affected by temperature.
Growth potential in the late winter to early spring period in the
warm-temperate New Zealand climate appeared to be strongly related to the
ability of plants to grow at 5deg.C. The most rapid growing populations at
5deg.C (`Daeno', ML-48-65) originated from continental climates. Differences of
up to 21% in 2C nuclear DNA amounts were measured between the white clover
populations by microdensitometry. The results were generally consistent with
the prediction that large genome size is associated with capacity for growth at
low temperatures, whereas small genome size is associated with superior growth
at higher temperatures. The two closely-related Pitau and G49 populations were
an exception to this trend.
Keywords dry matter allocation; genome size; leaf growth;
leaf phenology; Trifolium repens
New Zealand Journal of Agricultural Research, 1999, Vol. 42: 9-17
0028-8233/99/4201-0009 $7.00/0 (c) The Royal Society of New Zealand
1999
PDF file of entire paper: medium quality (737K); (scanned from paper original: notes about this process)
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