Drought Tolerant Corn Hybrids Yield More in Drought Stressed Environments with No Penalty in Non stressed Environments
The potential benefit of drought tolerant (DT) corn (Zea mays L. hybrids may depend on drought intensity, duration, crop growth stage (timing) and the array of drought tolerance mechanisms present in selected hybrids. We hypothesized that corn hybrids containing DT traits would produce more consistent yields compared to non DT hybrids in the presence of drought stress. The objective of this study was to define types of production environments where DT hybrids have a yield advantage compared to non DT hybrids. Drought tolerant and non DT hybrid pairs of similar maturity were planted in six site years with different soil types, seasonal evapotranspiration (ET) and vapor pressure deficit (VPD) representing a range of macro environments. Irrigation regimes and seeding rates were used to create several micro environments within each macro environment. Hybrid response to the range of macro and micro environmental stresses were characterized in terms of water use efficiency, grain yield, and environmental index. Yield advantage of DT hybrids was positively correlated with environment ET and VPD. Drought tolerant hybrids yielded 5 to 7% more than non DT hybrids in high and medium ET environments >430 mm ET) corresponding to seasonal VPD greater than 1200 Pa. Environmental index analysis confirmed that DT hybrids were superior in stressful environments. Yield advantage for DT hybrids appeared as yield dropped below 10.8 Mg ha 1 and averaged as much as 0.6 1 Mg ha 1 at the low yield range. Hybrids with DT technology can offer a degree of buffering against drought stress by minimizing yield reduction, but also maintaining a comparable yield potential in high yielding environments. Further studies should focus on the physiological mechanisms presented in the commercially available corn drought tolerant hybrids.
Front. Plant Sci.