TILLERING AND LEAF PRODUCTION IN WHEAT AS AFFECTED BY TEMPERATURE AND LIGHT INTENSITY

Abstract

The pattern of tillering developed during vegetative growth of well-spaced wheat plants agreed closely with calculation, if one assumes constant rates of leaf and tiller emergence. The average number of leaves formed between the appearance of successive tillers on an axis can be calculated from the ratio between the total number of leaves and tillers, and provides an estimate of apical dominance.The increase in total number of leaves per plant obtained by increases in light intensity over the range 200 to 2500 ft-c was brought about by an increase in both the rate of leaf emergence on individual axes and the rate of tillering. As the rate of tillering increased to a greater extent than the rate of leaf emergence, apical dominance was reduced. An increase in temperature over the range 10–25 °C also increased the total number of leaves and tillers, but the rate of leaf emergence was stimulated more than the rate of tillering so that apical dominance was increased.These effects of the environment on the relationship between leaf and tiller production are attributed to the close dependence of tillering on the supply of assimilates.