The effect of spacing on the growth of two genotypes of perennial ryegrass

Abstract

SummaryTwo clones of perennial ryegrass were planted along the radii of a fan in such a way that any group of four adjacent plants was approximately square, with spacings ranging from 3 to 30 cm. During the first year the amount of regrowth per vegetative plant was found to be related to the area available at the high densities, whereas at low densities there was little change in weight per plant with change in density. At high densities the number of tillers declined following defoliation, but at low densities it increased consistently. In the second year, the ratio of fertile to barren tillers was lower and ear emergence was later at high densities. Results indicated that the performance of the clones differed in each of three stages of regrowth. It appeared that early regrowth was better in the erect clone, but after the first week, and where the canopy remained open, the RGR of the prostrate clone was greater. In a dense sward the crop growth was greater in the erect clone indicating that better use was made of the available light.