Analysis of the Effects of Stomatal Frequency and Size on Transpiration and Yield of Wheat (Triticum aestivum L.)

In order to determine the effects of stomatal size and frequency on transpiration rate and yield in wheat, an experiment based on RCBD was performed in glasshouse condition using 21 drought tolerant cultivars. Stomatal frequency was measured in microscopic fields of leaf impressions taken from middle parts of flag leaves. Transpiration rate was expressed as the slope of the linear relationship between detached leaf weight loss (adjusted based on the leaf area) and time after cutting. Another experiment was conducted in the field condition in order to determine the yield of the same cultivars. Significant differences were found among cultivars in terms of transpiration rate, stomatal frequency, stomatal size and yield. However, stomatal characteristics were found to be poorly correlated with both yield and transpiration rate. Transpiration rate was found to be weakly correlated with stomatal size while yield was poorly correlated with stomatal number. More than 90% of total variation of transpiration rate and yield was attributed to unknown sources of variation and could not be explained by variation in stomatal characteristics.