Eric Adee*, Kraig Roozeboom, Guillermo R. Balboa, Alan Schlegel and Ignacio A. Ciampitti
Descarga articulo completo: https://doi.org/10.3389/fpls.2016.01534

Abstract:
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.
Keywords: corn, drought tolerant, yield, genotype, management, environment