Improving annual yields of sugars and crude protein by recurrent selection within diploid ryegrass breeding populations, followed by chromosome doubling and hybridisation

Recurrent combined phenotypic and family selection within restricted breeding populations of perennial ryegrass (Lolium perenne L.) followed by chromosome doubling and hybridisation with tetraploid Italian ryegrass (L. multiflorum Lam.) is being used at IGER to combine improved water-soluble carbohydrate (WSC) concentration of herbage with improved dry matter yield. A plot experiment was established in 2001 to assess progress under a 7 cut management (including 2 silage cuts) by comparing our new varieties of perennial and hybrid ryegrass with our older ones. In the first harvest year (2002), the newest perennial ryegrass variety with an intermediate heading date (Ba13582) yielded 49% more WSC than the oldest one (S321), and the newest hybrid variety (AberEcho) yielded 69% more WSC than the old hybrid variety (Augusta). These gains in WSC yield resulted from combinations of improved WSC concentration and improved dry matter yield. However, differences among varieties in yield of crude protein in this first harvest year were small because the newer varieties had significantly lower crude protein concentrations.