Low Temperature Growth in a Controlled Environment of Trifolium repens Plants from Northern Latitudes

Abstract

The variation in low temperature growth of several types of T. repens collected in northern Britain, UK, and sites where low temperature-adapted white clover plants may be found were investigated. Ecotypes (25) and selected genotypes of T. repens [cultivars, S.184, Kent and S.100,] were screened for shoot growth at low temperature and irradiance in a cold cabinet. A clinal relationship was indicated between low temperature growth and the winter temperature at the place of origin. One ecotype exhibited a marked deviation from this climatic cline. Two ecotypes exhibited good growth of stolons at soil temperatures below 9.degree. C. It may be possible to increase the value of T. repens in the uplands of Britain by breeding varieties which are capable of active growth at low soil temperatures. Raw plant material for this breeding can be found in lowland and upland areas of northern Britain. Small- to medium-leafed ecotypes produced more shoot growth than small-leafed types. Suggestions are made as to the type of plant which can provide raw breeding material and the habitat in which these plants may be found. Problems encountered in measuring shoot growth of T. repens are discussed.