Crop physiology: Disease effects and yield loss

Abstract

The growth of a crop is regulated by the summation of genetic and environmental limitations, and may conveniently be divided into several developmental stages. These stages often have been studied in isolation by plant physiologists, and the factors limiting each stage examined in detail. This information may be used to produce a model of crop growth, which can usefully highlight the limitations (in a physiological sense) imposed on development at the various stages, This, combined with a knowledge of the behaviour and interactions of components of yield, may be of great significance to studies of reduction in yield caused by pathogens, and may be used as a basis for deciding on sampling times and methods. This approach may also be useful in the interpretation of disease/yield loss relationship. The principles involved in this type of analysis are best illustrated by work on cereals and their foliar pathogens.