extremely significantqualified
The correlation between δ 13 C values during the three determination periods at the grain-filling stages with grain yield and WUE reached an extremely significant level, and different water conditions had no effect on the correlation between the δ 13 C values with grain yield and WUE , which is consistent with a large number of previous studies ( Wright, Rao & Farquhar, 1994 ; Condon, Richards & Rebetzke, 2004 ).