Effect of delayed irrigation at jointing stage on canopy temperature and leaf water use efficiency of winter wheat in wide-precision planting pattern

Optimal water-saving and high-efficiency irrigation regime of winter wheat were investigated during 2012—2013winter wheat growing season,at Experimental Station of Shandong Agricultural University. Two types of planting patterns( wide-precision planting pattern and conventional-cultivation planting pattern) and three different irrigation regimes( no irrigation at any time during the growing season,irrigation of 60. 0 mm at jointing stage,and irrigation of 60. 0 mm at 10 days after the jointing stage) were conducted to study the effect of delayed irrigation at jointing stage on canopy temperature,photosynthetic rate,transpiration rate,leaf water use efficiency,and grain yield of the winter wheat. The results showed that in the wide-precision planting pattern,compared with conventional-cultivation planting pattern,delayed irrigation at jointing stage significantly increased the canopy temperature,photosynthetic rate,and transpiration rate in flag leaves. In the late winter wheat growth stages,delayed irrigation at the jointing stage significantly increased the efficiency of leaf water use and achieved a reasonable water use efficiency and grain yield in the wide-precision planting pattern. Delayed irrigation at the jointing stage had no significant effect on the 1000-grain weight in both planting patterns; however,delayed irrigation at jointing stage significantly increased the number of kernels per spike and grain yield in the wide-precisionplanting pattern. The leaf water use efficiency and grain yield of the winter wheat suggest that winter wheat in wideprecision planting pattern should be irrigated with 60 mm of water at 10 days after the jointing stage to achieve reasonable water use efficiency and grain yield in North China.