Canopy temperatures of wheat: relationships with yield and potential as a technique for early generation selection

Abstract

It is shown that, for bread wheat, air-canopy temperature difference correlates significantly with grain yield, especially when measurements are taken later in the day, We discuss the potential of this technique as an early generation selection technique for high yielding varieties. In this context, we show that temperature measurements in spaced plants (mimicking the F2 generation planting arrangement) correlate as well with the yields of solid stands as do measurements on the solid stands themselves. We investigate the physiological basis for the relationships between air-canopy temperature difference and grain yield. There appear to be high positive correlations for stomatal conductance and photosynthetic rate with grain yield. We speculate about the physiological characteristics that may be responsible for these relationships. Durum wheats show a different behavior, in that there are no significant correlations for air-canopy temperature difference, stomatal conductance, and photosynthesis with grain yield.