Winter wheat yield was positively correlated with innorthern China including Zone I and Zone II, however was nega-tively correlated with Tmeanin southern China including Zone IIIand Zone VIII (Fig. 3). In northwestern China, spring wheat yieldwas negatively correlated with Zone VI, but positivelycorrelated with in high altitude Zone VII. The positive (neg-ative) correlations suggested that yield was positively (negatively)affected by increase in Tmean.