Improving evaluation and selection criteria of ryegrass varieties by linking phenotypic from research and commercial farm environments

Varieties, however were found to differ in their suitability for intensive grazing, with variety significantly influencing the level and quality of grazed herbage produced. When assessed in animal grazed plots, tetraploid varieties were found to have significantly better grazing efficiency than diploids. This study identified increased dry matter digestibility, free leaf lamina and tiller mass as key selection criteria to develop improved grazing varieties, as they were found to significantly improve grazing efficiency.

Under simulated grazing, perennial ryegrass was found to be better suited to grazing systems than hybrid ryegrass varieties tested, as it maintained high herbage quality throughout the year and had better yield stability. This study also demonstrated that annual herbage production was not limited by sward density.<br><br>This thesis provides evidence that varieties differ greatly in their suitability for grazing, due to differences in their structural and chemical characteristics.

However, to assess and to encourage breeders to prioritise these characteristics, evaluation programmes need to change by assessing the interaction of plant and animal.