High temperature influence on limited transpiration response at elevated vapor pressure deficit in maize' Avat Shekoofa and Thomas R. Sinclair
Shekoofa, A.  2017.  An abstract-accepted, Inter-Drought V, India Feb 21-25, 2017.

Drought impacts nearly all crop production for at least a limited period of time across the US Corn Belt. Temperature and vapor pressure deficit (VPD) are two important environmental factors influencing stomatal conductance and transpiration under water deficit stress. A limited transpiration rate (TRlim) trait expressed under high VPD (> ~2kPa) has been shown to offer an approach to increase crop yield in water-limited areas. Previous studies at moderate temperatures (32C and lower) identified maize (Zea mays L.) hybrids that express the TRlim trait. A critical question is whether the TRlim trait is also expressed by these hybrids under temperatures up to 38C, which are relevant in environments where maize may be grown. Among twelve maize hybrids, five of them failed to express the TRlim trait at 38C but seven hybrids had sustained expression of the trait at 38C. The loss of expression of the TRlim response in the five hybrids was found to occur in the very narrow range of temperature increase from 36 to 38C. The next question is how long it takes for stomatal conductance back at levels the same as before the high temperature (38C) treatment? The result of a series of experiments on maize hybrids with expressing TRlim and not expressing the trait indicated that the recovery in the hybrids with expressing TRlim occurred quickly (~ 6hrs). The genetic differences in water use among these maize hybrids could be useful in selecting hybrids that are especially well adapted for temperature conditions in a targeted production area.