A MODEL OF WHEAT-GRAIN GROWTH AND ITS APPLICATIONS TO DIFFERENT TEMPERATURE AND CARBON-DIOXIDE LEVELS

Kernel growth after anthesis is simulated as a function of the potenti al kernel growth rate, current photosynthate production and mobilisati on of stored reserves. The potential growth rate of the kernel is simu lated as two temperature-sensitive processes, cell production and cell growth. The difference between the potential and actual growth rates of the kernel depends on the carbon supply to the free space of the ke rnel endosperm, while the carbon supply is itself affected by the actu al kernel growth rate. Sensitivity analysis showed that the growth rat e of the grain per plant is most sensitive to the potential growth rat e of the kernel and number of kernels per plant. This model is able to simulate the observed rates of grain growth and leaf senescence from anthesis to physiological maturity for wheat plants grown in two CO2 c oncentrations. The simulated temperature response of grain growth agre es well with the experimental observations.