Abstract: Ten species of winter wheat which grown in Northern China were selected in this study,they were treated by two water conditions: Full-Irrigation and Insufficiency-Irrigation(Rainfall).Tthen we analyzed the correlation between the photosynthetic rate and the yield.The result showed that under Full Irrigated condition,both the photosynthetic rate and the yield were higher than that under insufficiency irrigation's.The positive correlativity between the photosynthetic rate and the yield was remarkable during the procreate growth period.During the heading-blooming and the beginning of grain-filling stage,the correlation between the photosynthetic rate(Natural light) and the yield was the most remarkable.For the photosynthetic rate(LED),the most remarkable correlation was during the stage of heading-blooming,the beginning grain-filling and the mid-grain-filling.Therefore,more irrigation during heading-blooming and grouting stage could enhance the photosynthetic rate and increase the yield of winter wheat.

Key words: Winter wheat, Water, Photosynthetic rate, Yield, Correlation(relativity)