A model of bean (Phaseolus vulgaris L.) growth types I–III: Factors affecting yield

Abstract A per capita, supply-demand regulated, age-structured population dynamics model of the growth and development of the common bean ( Phaseolus vulgaris L. ) is used to simulate three growth types in Brazil. The model assumes that the crop canopy is composed of age-structured subpopulations of leaf, stem and root masses, and of fruit numbers and associated masses. The dynamics of each subpopulation is modelled using an age-structured distributed-maturation time model with attrition. The interaction of photosynthate supply to demand regulates the rudiments of bean physiology. The daily rate of photosynthate production is estimated using the Gutierrez-Baumgartner functional response model, with the genetic demand for carbon as modified by nitrogen and water availability being the major controlling variable in the model. The ratio of the realized photosynthate production rate (i.e. the supply) to the maximum assimilation rate for drymatter (i.e. the demand) controls all drymatter allocation rates, the initiation rates of new subunits (i.e. fruits) and their associated masses, and the shedding rates of different aged buds and fruits.