Genotypic and environmental variance for white clover yield in a commercial breeding programme

Teagasc research demonstrates that incorporating white clover (Trifolium repens L.) into grazing swards contributes additional nitrogen (N) to grassland and increases forage quality leading to increased milk yields relative to grass-only swards, contributing to the economic and environmental sustainability of pastoral-based production systems. Two hundred and fifty eight full-sib white clover families were evaluated over three harvest years. Total yield of grass and clover was measured and the results were used to guide the development of new synthetic cultivars. In this paper we determine the genotypic and environmental variance and heritability of yield. The objective is to determine the potential of utilising these families to establish a training population to develop and assess genomic selection approaches for white clover breeding to improve agronomic performance. We found sufficient genotypic and phenotypic variation within this population and broad-sense heritability for forage yield was calculated as 0.76, indicating selection for forage yield will result in genetic gain