Mortal Response and Growth of Individual Plants in a Population of Orchardgrass (Dactylis glomerata L.) : III. Relationship between tiller density and tiller weight

Abstract

Orchardgrass (Dactylis glomerata L.) were grown at various densities in experimental field. The development of plant (genets) and tillers in each density were investigated. Although the relationship between mean plant weight and density had a tendency to conform to the so called competition-density law, the development of the plant population in higher densities was not conformed to the -1.5 power law through time. Tiller death took place in the majority of individual plant in the population and the rate of growth of surviving tillers was related to the tiller death. Consequently, the changes in tiller densities in various plant densities were showed to follow the common thinning line in the period of vegetative growth. However, during the reproductive phase and under a frequent cutting treatment, it was considered that the relationship between mean tiller weight and tiller density might alter with the lapse of time, with no density-induced thinning. The results were discussed by comparing with those obtained from other studies on grass populations.