Relative winter performance of cocksfoot lines in first- and fourth-year swards

Abstract

Thirteen cocksfoot (Dactylis glomerata) lines were ranked for winter yield as first and fourth-year swards when grown in the field at Canberra. Yield rankings of five lines were similar for young and old plants, while five lines achieved a higher ranking and three lines a lower ranking as older plants. Change in ranking between young and old plants was apparently due in part to a changing emphasis in the relative importance of the growth components ; in young plants tiller number was the main component of winter yield whereas in old plants growth per tiller was the more important component. Some other factors that might influence the assessment are also discussed. It is suggested that assessment of winter growth of cocksfoot lines for the long ^term is more realistic when measurement is based on plants at least two years old.