ISHS Acta Horticulturae 416: IV International Symposium on Computer Modelling in Fruit Research and Orchard Management
DETERMINISTIC MODELS FOR FRUIT GROWTH |
| Authors: | P.W. Gandar, A.J. Hall, H.N. de Silva |
| Abstract:
Many aspects of fruit growth can be modelled using systems of ordinary differential equations in which rates of change of fruit properties are expressed as functions of the state of the fruit and of environmental forcing factors. However, there is no theory for determining the correct forms for these equations. Models must therefore be constructed in a 'top-down' fashion, i.e., by looking at data and asking what sort of equation, or system of equations, might have solutions that match them. The difficulty then is that there are usually many candidate models with solutions that match a given data set. In this paper, we illustrate some top-down models which can be fitted to singlesigmoid (e.g.., apples) and 'double-sigmoid' (e.g., kiwifruit) growth curves and outline methods for including an environmental variable such as temperature in these models. We then discuss various ways in which these simple models might be related to underlying processes such as cell division and expansion, illustrating some results by simulation. We conclude that there is considerable scope for further development of deterministic models (i), as practical forecasting tools and (ii), as a means of representing physiological concepts at various levels of complexity. At the same time, these models should never be viewed as anything more than convenient, rational empiricisms. | |
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