Adaptation to low fertility hill country in New Zealand of white clover lines selected for differences in response to phosphorus

Abstract

White clover breeding lines developed as high and low P‐responsive, in glasshouse selection trials, were compared, over three years, with 17 other breeding lines and cultivars for growth in four soil‐fertility treatments under two defoliation treatments on a hill‐country farm. Differences between P‐response groups were transitory and biologically insignificant. Selection for differences in response to P in a controlled environment was not successful in identifying white clover germ‐plasm adapted to low P hill‐country soils. White clover breeding lines and cultivars that achieved high growth over the 3‐year duration of the trial had New Zealand parentage and were all medium to small leaf types.