Abstract
This experiment was carried out to evaluate the microclimate of wheat canopy, growth and yield characteristics of wheat under north-south and east-west row orientation. The variety used in this experiment was "AG South 2000", which was developed in USA. Solar radiation, air temperature, relative humidity, and soil temperature were monitored by data logger from March to May in 2002, The ratio of light penetration to the bottom from the upper canopy was 36.8% in north-south and 21.4% in east-west row orientation. Temporal march of light penetration to the bottom from March to May decreased as wheat developed canopy structure and decreased a little from May as plant were matured. The highest light penetration to the bottom from upper canopy occurred at 13：00 in both north-south and east-west row orientations, respectively which were 36 times in north-south and 27 times in east-west row orientation, respectively. Daily maximum temperature at the bottom of canopy occurred at 14：00 with 29 times in north-south, while 19 times were obtained at 14：00 and 15：00, respectively in east-west row orientation. Relative humidity at the bottom of the canopy in east-west yow orientation showed higher than that of north-south row orientation. Occurrence of daily maximum soil temperature of north-south showed one hour later compared with east-west yow orientation. 1000 grain weight and test weight of north-south row orientation was higher than those of east-west vow orientation. Correlation coefficient between solar radiation of upper canopy and 1000 grain weight showed r=$0.8132^{*}$, and between air temperature of upper canopy and number of spikes per $\textrm{m}^{2}$ and 1000 grain weight showed significant positive correlation with r=$0.8139^{*}$, and r=$0.8293^{*}$, respectively.
