Breeding high energy grasses for Australia and New Zealand

Abstract

There are currently a range of programmes breeding ryegrasses with enhanced water-soluble carbohydrate concentrations leading to enhanced metabolisable energy (ME) contents when this herbage is consumed by grazing ruminants. High ME concentrations in grasses have the potential to increase milk and meat production through improved energy supply and more efficient rumen fermentation. However, the first 'high sugar' grass cultivars sown in Australia and New Zealand have not always delivered the animal production benefits that have been realised when these cultivars were sown in the UK. This illustrates not only the need to develop agronomic practices that are suited to exploiting the potential of germplasm with high energy concentrations but also the need to not view the high energy trait in isolation from other breeding objectives such as adaptation, seasonal production and disease resistance. Keywords: perennial ryegrass, carbohydrate, sugar, fructan, breeding