Stomatal Behavior of Wheat Cultivars in Relation to Their Transpiration, Photosynthesis, and Yield1

Abstract

AbstractWheat cultivars were found to differ widely in their stomatal aperture under conditions of adequate moisture supply. A field study was carried out to determine whether these differences were related to short‐term transpiration (measured by a hygrosensor cuvette over periods of less then 1 min), short‐term photosynthesis (measured by the uptake of 14CO2 over a period of 20 sec), long‐term water consumption (determined from soil moisture data over periods of several weeks), and grain yield. Rank correlations between the various attributes were determined. Ten wheat cultivars were used in 1 year, 11 cultivars in the other year. Leaf permeability (measured by means of a viscous‐flow porometer) was well correlated to stomatal aperture (measured by means of silicone rubber impressions), and was therefore used as an index of stomatal aperture. Leaf permeability was significantly rank‐correlated with short‐term transpiration (r = 0.97 to 0.98), with short‐term photosynthesis (r = 0.86 to 0.84) and with grain yield (r = 0.70 to 0.74), but not with water consumption (r = 0.01 to 0.22), which was nearly the same for all cultivars. Yields of the cultivars ranged between 4,000 and 5,200 kg ha−1 in the first year, and between 4,250 and 6,150 kg ha−1 in the second year. It is suggested that wheat cultivars having wider somatal aperture produce higher yields without consuming more water, and that the porometer method may be employed in wheat breeding programs.