The pastoral significance, adaptive characteristics, and grazing value of white clover (Trifolium repens L.) in dryland environments in Australia: a review

The importance of white clover as a pasture legume of international signifi cance has led to major investment in research on ecophysiology, germplasm c onservation, and white clover improvement. Despite the agronomic merit and economic significance of white clover, Australia lacks white clover cultiva rs that possess adaptive characteristics for persistence in mixed swards un der sheep and cattle grazing. The major problem with contemporary white clo ver cultivars is that clover biomass fluctuates widely from year to year. T his lack of reliability, particularly in dryland environments, is largely d ue ro poor survival during summer moisture stress that is common to much of the Australian white clover zone. Factors such as edaphic constraints, int olerance of grass competition and close grazing, and lack of winter growth in cold environments also influence the contribution of white clover to pas ture performance. This paper considers the mechanisms of regeneration, adap tive characteristics, and significance of white clover for animal productio n, and reflects on breeding objectives for white clover improvement.