Irrigation Management of Emerging Drought-Tolerant Corn Hybrids.

Drought-tolerant and standard corn hybrids were compared at four plant populations at Topeka, KS and three populations at Scandia, KS under three irrigation levels in 2012.  At Topeka, both types of hybrids were nearly identical in their yield and linear response to increasing populations when water was not a limiting factor.  At Scandia, there was very little yield response to population in the regular hybrids and a decreasing yield trend in the drought-tolerant hybrids as population increased.  However, averaged across populations, the drought-tolerant hybrids out-yielded the regular hybrids at the highest irrigation level. As water became more limiting, the drought-tolerant hybrids sustained yields at higher populations at both sites.  When water availability was reduced further, the yields of the drought-tolerant hybrids were as much as 20% greater than regular hybrids at Topeka and Scandia. Furthermore, the drought-tolerant hybrids demonstrated the ability to sustain populations as much as 10,000 plants/a higher than the standard hybrids at both study sites.