Evaluation of Commercial Drought Tolerant Corn Hybrids for the Humid MID-South.

Corn hybrids designated “drought tolerant” (DT) from three commercial seed companies were evaluated in order to determine the benefit of DT technology in a mid-south environment that may receive adequate but often poorly timed rainfall. Field research was conducted in 2014 and 2015 at Milan, TN where hybrid response to stress was evaluated at two planting dates and in non-irrigated and irrigated environments. Two hybrids of similar maturity were selected from each company; one with the DT trait and one without. Treatments were arranged within a randomized complete block with 6 replications. Total dry matter, plant height, collar count, and leaf temperature were recorded on five plants per plot at the V-6, V-12 and R-1 growth stage. Adaxial and abaxial stomatal conductance readings were also taken at these stages. Yield, grain weight, ear size, stalk weight, and ear weight were recorded at harvest. All data were analyzed using SAS 9.4.

In 2014, the non-irrigated trials received enough rainfall to create a high yielding environment. Since the DT hybrids were only stressed for short periods of time throughout the growing season, we were unable to evaluate growth under intense stress conditions, however, it was determined that hybrids with the DT technology are quite competitive in high yield conditions. Of the data recorded, 500 seed weight and abaxial stomatal conductance consistently explained more of the yield predictions than any other data, however, predictions still varied between companies.

DT corn hybrids could potentially be an option for growers producing corn in humid regions that only sustain brief periods of drought throughout the growing season. However, more research is needed to better understand these novel technologies and how they achieve their ability to tolerate drought stress.