Morphological characteristics and agronomic merit of white clover (Trifolium repens L.) populations collected from northern New South Wales

A set of white clover (Trifolium repens L.) populations collected from old pasture sites in northern New South Wales was characterised in situ at the collection sites and under uniform glasshouse conditions, and then evaluate d for agronomic merit in the field. The data were examined to determine whe ther ecotype development through genetic differentiation had occurred in th ese white clover populations, and to assess their potential value for futur e breeding. Environmental conditions at the collection sites represented a wide diversity of rainfall, altitude, soil type, companion grass, and grazi ng intensity conditions. The populations generally were found to be medium- leaf and mid- to late-flowering and derived from early New Zealand introduc tions to Australia. The populations showed significant (P < 0.05) variation in morphological characteristics (leaf size and stolon characters) and thi s variation was expressed in all 3 environments. It was concluded that sign ificant genetic differentiation affecting stolon and flowering characterist ics had occurred, with implications for agronomic value. A small cluster of the populations was found to possess useful characteristics for white clov er breeding where persistence in dryland environments is the primary breedi ng objective.