Abstract: In small-plot and field trials with 4 cv. of spring wheat and 1 cv. of winter wheat,CCC was applied as foliar spray or as seed treatment in 1970—1972. In all trials, the application of CCC reduced the stem length and increased the number of ears perplant and the number of grains per ear. The dry weight of grains per ear and the1000-grain weight were also increased. The final grain yield of the treated plots was 6%–31% higher than that of the controls. Application of CCC caused a marked in-crease in total dry weight of the plant and a greater proportion of their total drymatter concentrated in grains than that of the control plants. Increase in dry weight of the grain was closely correlated with the change in dryweight of the leaf and stem. The dry weight of the leaf and stem actually increasedat the beginning of the filling period, while the increase in dry weight of the grain wasat a low rate. When the increase in grain dry weight reached its maximum about18–30 days after anthesis, the amount of materials lost from the leaf and stem wasalso the greatest. The increase in grain dry weight of the CCC treated plants was lessthan that of the control plants during the first half of the filling period. As the maximum rate of grain dry weight increment approached, however, the increase ingrain dry weight of the CCC treated plants rose to much higher rate than that of the controls, and such a high level of increment was maintained by the treated plantsuntil maturity. The total dry matter lost from the leaf of the treated plants was also greater than that from the controls. These results indicated that an important effect of CCC on wheat is to promote the accumulation of materials in grains during the laterstage of the filling period.