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AberBite (BA13800) - Lolium perenne tetraploid late heading

Perennial ryegrass seed sales comprise 69% of the UK market making it the most important species in UK grassland agriculture. The IBERS breeding programme has concentrated on the development of varieties that provide excellent performance for the conventional agronomic traits assessed in statutory National List (NL) and Recommended List (RL) trials but with the added benefit of improved ‘public good’ traits which provide an additional environmental or efficiency benefit, both to agriculture and to the wider public. Traits are chosen as a result of more fundamental research at IBERS, thus new forage varieties become a delivery mechanism for the benefits of that research.

Recurrent combined phenotypic and family selection within restricted diploid breeding populations is effective in combining improved dry matter yield (DMY) with increased water-soluble carbohydrate (WSC) content and good persistency. But population improvement leads to the accidental fixation of deleterious genes, and thus there will always be potential to make gains in DMY by hybridising plants developed from different breeding populations. Tetraploidy offers a simple means of preserving heterosis over several generations of seed multiplication. However, chromosome doubling tends to reduce persistency and there is little evidence for heterosis with WSC. Therefore top cross families were generated using a recently chromosome-doubled population as male parent and selected female parents from different tetraploid cultivars.

The late flowering tetraploid perennial ryegrass variety AberBite (Ba13800) is a topcross family which used a selected Ba11965 genotype as the mother plant and several selected Ba13525 (chromosome-doubled AberAvon) genotypes as pollen donors. Following trials of the second generation seed in pre-NL trials, AberBite demonstrated exceptionally high seasonal DMY and high WSC content and was selected to be submitted for NL/RL testing.

AberBite achieved NL status in 2008 and was placed on the England & Wales, the Scottish and Northern Irish RL’s in 2009.