Water Use and Grain Yield in Drought-Tolerant Corn in the Texas High Plains

Drought is an important factor limiting corn (Zea mays L.) yields in the Texas High Plains, and adoption of drought-tolerant (DT) hybrids could be a management tool under water shortage. We conducted a 3-yr field study to investigate yield, evapotranspiration (ET), and water use efficiency (WUE) in DT hybrids. One conventional (33D49) and 4 DT hybrids (P1151HR, P1324HR, P1498HR, and P1564HR) were grown at three water regimes (I-100, I-75, and I-50, referring to 100, 75, and 50% ET requirement) and three planting densities (PD) (5.9, 7.4, and 8.4 plants m(-2)). Yield (13.56 Mg ha(-1)) and ET (719 mm) were the greatest at I-100 but WUE (2.1 kg m(-3)) was the greatest at I-75. Although DT hybrids did not always have greater yield and WUE than 33D49 at I-100, hybrids P1151HR and P1564HR consistently had greater yield and WUE than 33D49 at I-75 and I-50. Compared to 33D49, P1151HR and P1564HR had 8.6 to 12.1% and 19.1% greater yield at I-75 and I-50, respectively. Correspondingly, WUE was 9.8 to 11.7% and 20.0% greater at I-75 and I-50, respectively. Greater PD resulted in greater yield and WUE at I-100 and I-75 but PD did not affect yield and WUE at I-50. Yield and WUE in greater PD (8.4 plants m(-2)) were 6.3 to 8.3% greater than those in smaller PD (5.9 plants m(-2)). The results of this study demonstrated that proper selection of DT hybrids can increase corn yield and WUE under water-limited conditions.