Hereford, TX, United States
Hereford, TX, United States

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Hao B.,Texas AgriLife Research Center | Xue Q.,Texas AgriLife Research Center | Marek T.H.,Texas AgriLife Research Center | Jessup K.E.,Texas AgriLife Research Center | And 7 more authors.
Agronomy Journal | Year: 2015

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 (I100, I75, and I50, 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 I100 but WUE (2.1 kg m-3) was the greatest at I75. Although DT hybrids did not always have greater yield and WUE than 33D49 at I100, hybrids P1151HR and P1564HR consistently had greater yield and WUE than 33D49 at I75 and I50. Compared to 33D49, P1151HR and P1564HR had 8.6 to 12.1% and 19.1% greater yield at I75 and I50, respectively. Correspondingly, WUE was 9.8 to 11.7% and 20.0% greater at I75 and I50, respectively. Greater PD resulted in greater yield and WUE at I100 and I75 but PD did not affect yield and WUE at I50. 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. © 2015 by the American Society of Agronomy, 5585 Guilford Road, Madison, WI 53711. All rights reserved.

Hao B.,Texas AgriLife Research Center | Xue Q.,Texas AgriLife Research Center | Marek T.H.,Texas AgriLife Research Center | Jessup K.E.,Texas AgriLife Research Center | And 4 more authors.
Agricultural Water Management | Year: 2015

Anticipated water shortages pose a challenge to the sustainability of maize (Zea mays L.) production on the Texas High Plains. Adoption of drought-tolerant (DT) hybrids is a critical management strategy for maize production under water-limited conditions. However, limited information is available concerning water use by recently released DT hybrids. The objective of this study was to investigate the soil profile water extraction, evapotranspiration (ET), water use efficiency (WUE), and grain yield of one conventional and one DT hybrid. Field experiments were conducted in 2012 and 2013. The DT hybrid (AQUAmax™ P1151HR) and the conventional hybrid (33D49) were grown under three water regimes (I100, I75 and I50, referring to 100%, 75% and 50% of the ET requirement, respectively). The depth of soil water extraction was not affected by hybrid or water regime with the maximum extraction depth being 1.2-1.4m. Water extraction was higher at I50 than at I75 and I100. The maximum soil water extraction at I50, I75 and I100 occurred in 0.6-0.8m, 0.6-1.0m and 0.8-1.0m soil layers, respectively. Hybrid differences in soil water extraction were found in 2012, mainly at the grain-filling stage. At I100, P1151HR had less soil water extraction than 33D49. Under water stress conditions at I50, P1151HR had less soil water extraction in the upper soil layers but more water extraction in the deeper layers than 33D49. P1151HR had the same or less seasonal ET as compared to 33D49, indicating that the AQUAmax hybrid did not use more water than the conventional hybrid. P1151HR had higher yield and WUE than 33D49, particularly under the lower water regimes. On the average, yield and WUE of P1151HR were 6% and 9%, 14% and 17%, 24% and 30% higher than those of 33D49 at I100, I75 and I50, respectively. Higher yield of DT hybrid was associated with a higher biomass, a greater harvest index, and heavier kernel weight as compared to the conventional hybrid. © 2015 Elsevier B.V.

Hao B.,Texas AgriLife Research Center | Xue Q.,Texas AgriLife Research Center | Bean B.W.,Nextsteppe Seeds Inc. | Rooney W.L.,Texas A&M University | Becker J.D.,Nextsteppe Seeds Inc.
Biomass and Bioenergy | Year: 2014

Photoperiod-sensitive sorghum (Sorghum bicolor L. Moench) (PSS) has been identified as a potential bioenergy crop. However, little information is available for water and nitrogen (N) management in PSS in the Texas High Plains. The objectives of this study were to optimize water and N management for improving biomass yield, and to maximize water and N use efficiency in PSS. Two field experiments were conducted at different N rates (experiment I) and irrigation levels (experiment II). In experiment I, biomass yield ranged from 12Mgha-1 to 18Mgha-1 in two years. The optimum N rate and N use efficiency (NUE) were 183kgha-1 and 78kgkg-1 in 2010, and 148kgha-1 and 90kgkg-1 in 2011. In experiment II, biomass yield and evapotranspiration (ET) increased with increasing irrigation, but water use efficiency (WUE) was not affected by irrigation. ET was about 500mm at full irrigation, 360mm at limited irrigation, and 240mm under dryland. Biomass yield ranged from 15Mgha-1 to 23Mgha-1, from 11Mgha-1 to 18Mgha-1, and from 8Mgha-1 to 13Mgha-1 at full and limited irrigation, and under dryland, respectively. WUE ranged from 30kgha-1mm-1 to 47kgha-1mm-1. Biomass yield and WUE varied among years but ET was relatively stable, suggesting higher WUE was due to increased biomass rather than reduced ET. The results of this study indicated PSS may achieve high biomass yield under limited irrigation. © 2014 Elsevier Ltd.

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