Selection Criteria in Grass Breeding. II. Effect, on Lolium perenne, of differences in population density, variety and available moisture

Abstract

A summary of the objectives of the present studies has been presented in a previous paper (Lazenby & Rogers, 1962): traditional methods used in the selection of improved grass varieties were reviewed together with a history of varietal assessment and some recent research developments of importance to both grass breeder and grassland agronomist. For full evaluation of selection criteria, the performance of the grass plant should be studied when the variables potentially affecting growth and development are controlled individually and in combination. Results were reported of an experiment designed to study the behaviour of one variety of Lolium perenne, S. 24, grown in different densities and under two moisture règimes. Data presented were total yield per unit area and the botanical components of such yield—number of plants, yield por plant, number and weight of sterile and fertile tillers—together with a statistical appraisal of their interrelationships (Campbell, 1962).