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

Aset 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 evaluated for agronomic merit in the field. The data were examined to determine whether ecotype development through genetic differentiation had occurred in these white clover populations, and to assess their potential value for future breeding. Environmental conditions at the collection sites represented a wide diversity of rainfall, altitude, soil type, companion grass, and grazing intensity conditions. The populations generally were found to be medium-leaf and mid- to late-flowering and derived from early New Zealand introductions to Australia. The populations showed significant (P < 0.05) variation in morphological characteristics (leaf size and stolon characters) and this variation was expressed in all 3 environments. It was concluded that significant genetic differentiation affecting stolon and flowering characteristics had occurred, with implications for agronomic value. A small cluster of the populations was found to possess useful characteristics for white clover breeding where persistence in dryland environments is the primary breeding objective.