Improving the resilience of white clover (Trifolium repens L.) to environmental stress through interspecific hybridisation

The ability of forage legumes to produce high yields of quality forage while exposed to periods of environmental stress is important if their value to sustainable livestock production systems is to be fully realised. White clover (Trifolium repens L.) is a high quality forage species and the most important forage legume of temperate grassland agriculture. Interspecific hybrids between the stoloniferous white clover and the drought-tolerant rhizomatous species Caucasian clover (T. ambiguum M. Bieb.) have been produced and, through a backcrossing programme, the rhizomatous growth habit of T. ambiguum has been introgressed into a white clover background with a view to improving the drought tolerance and resilience of white clover. The resulting hybrids have formed the basis of the IBERS white clover breeding population. Analysis of the response to drought of genotypes from that population has shown significant variation in the maintenance of leaf relative water content, stolon growth and dry matter yield, indicating the potential for improving the drought tolerance of white clover using this genepool. The implication of these results for exploiting this material in white clover breeding programmes is described