Evaluation of Drought Tolerant Maize Germplasm in a Controlled, Moisture Limited Environment.

Corn is highly dependent upon moisture availability to generate consistent and favorable yield.  Because moisture in rainfed corn production is often limiting at critical growth phases and aquifer depletion makes reliance upon groundwater for irrigation a tenuous situation at best, commercial hybrids have been developed that tolerate moisture stress.  We evaluated six commercial corn hybrids from three different companies.  Each company provided one hybrid designated moisture stress tolerant and another hybrid from a similar relative maturity group that was not.  Corn was grown in 4 sunlit, controlled environment chambers.  Hybrids were grown in a sand, clay, silt medium to which Hoagland’s solution was applied.  Evapotranspiration stress treatments were induced at 100, 75, 50, and 25% at 14 days after planting (DAP). Growth measurements were taken every 7 days and Pnet and moisture readings were recorded at 2 day intervals starting from 24 DAP to 32 DAP.  Relative injury, wax content, phenolic content, chlorophyll a, chlorophyll b, carotenoid content were measured 33 DAP.  At 34 DAP plants were harvested and vegetative and physiological parameters were measured including plant height, leaf number, leaf area, and total dry matter.  Differences among treatments were observed and will be discussed in our presentation.