| Under drought stress in the field, study was made on the morphology，photosynthetic characteristics and
yield components of three plant types of corm that were the flat type-Yuyu 22, intermediate type-Shendan 16 and compact type-Xianyu 335. The results showed that: (1) Drought stress led to leaf chlorophyll content of three corn varieties re-ducing significantly ，the chlorophyll content of Xianyu 335 was least affected by the drought stress, while the greatest im-pact was on Yuyu 22. (2) The Pn， Tr，Gs and Ci got significantly lower with increasing degree of drought stress. but the variation of WUE was opponent，and the heavier the drought stress， the higher WUE. WUE and Pn of Xianyu 335 was the highest ，while Yuyu22’s was the lowest. (3) Along with the deepening of drought stress level, the plant height，
ear length，ear linage, ear diameter, kernel number per row，1000-kernel weight and yield of three plant types of corn got significantly lower, but the rare top got longer. The rang of yield decrease of Yuyu 22 was the greatest，while that of Xianyu335 was the smallest. |