Evaluation of Drought-Tolerant Corn (Zea mays L.) Hybrid Performance in a High Yield, Non-Moisture Limiting Environment.

Growers in the Mid-South seek methods to limit the negative effects of drought, whether it be planting early or using drought-tolerant hybrids. Drought-tolerant corn hybrids have been selected to perform well in water-stressed environments. These products are marketed in Kansas, Colorado, and Nebraska to mitigate frequently occurring drought stress. In some years, growers in the Mid-South also experience periods of drought, especially in rain-fed, dryland production systems. However, in our geographic region, we receive approximately 140-152 cm a year. Some years, moisture is not limiting and in other years, drought negatively affects corn during June and July. This study was designed to evaluate drought-tolerant hybrids in optimal growing conditions to determine if this technology in any way limits our growers in good years. Drought-tolerant hybrids were selected and compared against a check, which was a high yielding, southern adapted hybrid DKC67-72. This hybrid has been at or near the top of yield trials at the majority of the Mississippi official variety trial locations the past several years. Corn was planted timely on March-21, March-22, and April-13, at high populations of 99K plants ha^-1 in Brooksville, 111K in Starkville, and 111K in Verona, MS, respectively. Because our objective was to evaluate these hybrids in a high yield environment, 336 kg N ha^-1 were applied in split-application. Relative maturity (RM) of evaluated hybrids ranged from 97 to 117 days. Across all three locations, the RM group 97-105 day hybrids on average produced 12% less corn grain yield than the control hybrid. The RM group 107-116 day hybrids on average produced 5% less corn grain yield than the check. In conclusion, in growing seasons with favorable environmental conditions and optimal agronomic inputs for fertility, weed control, and plant population, drought-tolerant hybrids do not perform as well as the southern-adapted hybrid.