Yield determination of maize hybrids under limited irrigation

ABSTRACT

Hybrid adoption, irrigation, and planting density are important factors for maize (Zea mays L.) production in semiarid regions. For this study, a 2-yr field experiment was conducted in the Texas High Plains to investigate maize yield determination, seasonal evapotranspiration (ETc), and water-use efficiency (WUE) under limited irrigation. Two hybrids (N74R, a conventional hybrid, and N75H, a drought-tolerant (DT) hybrid) were planted at three water regimes (I₁₀₀, I₇₅, and I₅₀, referring to 100%, 75%, and 50% of the evapotranspiration requirement) and three planting densities (PD 6, PD 8, and PD 10, referring to 6, 8, and 10 seeds m⁻²). At I₅₀, drought stress reduced grain yield by 4.78 t/ha for the conventional hybrid but only 4.22 t/ha for the DT hybrid, when compared to I₁₀₀. Although ETc decreased at I₇₅ and I₅₀, the highest WUE was found at I₇₅. The DT hybrid did not yield more than the conventional hybrid but had greater yield stability at lower water regimes and extracted less soil water. Drought decreased biomass, harvest index, and kernel weight but did not affect kernel number. Higher planting densities increased biomass and kernel number but decreased kernel weight. Kernel number and kernel weight of the conventional hybrid were more sensitive to planting density than the DT hybrid. These data demonstrated that limited irrigation at I₇₅ is an effective way to save water and maintain the maize yield in semiarid areas, and that DT hybrid shows a greater yield stability to plant density under water stress.

KEYWORDS:

• Drought-tolerant hybrid
• planting density
• water use
• water-use efficiency
• Zea mays L

Acknowledgments

We are grateful to Texas A&M AgriLife Research staff of Chance Reynolds, Choyce Reynolds, Brad Parker, Cole Pope, Bella Porras, Bronc Finch, and Preston Sirmon for their help in field and laboratory work. This research was supported in part by Texas A&M AgriLife Research Cropping System Program, Syngenta-US Seeds, Inc., the USDA-Ogallala Aquifer Program, and the USDA National Institute of Food and Agriculture Hatch Project, USA (TEX09438).

Disclosure statement

No potential conflict of interest was reported by the authors.