New Zealand Journal of Agricultural Research abstracts

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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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