A simple model of the relationship between plant density, plant biomass, and time.
The relationship between the wt. of above-ground biomass/unit area (y) the number of plants/unit area and time can be expressed in terms of arbitrary parameters. The equation given follows from the Shinozaki-Kira (rectangular hyperbola) relationship between crop biomass and plant density and the assumption that CGR at fixed y is independent of plant density. The equation adequately represented 7 contrasted sets of data from the literature, showing this assumption to be valid. Alternatives to the hypothesis that genotypic differences in yield-density relationships reflect genotypic differences in 'aggressiveness' of interactions between neighbouring plants are discussed.