Maize hybrid response to sustained moderate drought stress reveals clues for improved management

Authors: AO, SAMADANGLA - University Of Minnesota; RUSSELLE, MICHAEL - University Of Minnesota; Feyereisen, Gary; VARGA, TAMAS - University Of Minnesota; COULTER, JEFFREY - University Of Minnesota

Submitted to: Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/10/2020
Publication Date: 9/12/2020
Citation: Ao, S., Russelle, M.P., Feyereisen, G.W., Varga, T., Coulter, J.A. 2020. Maize hybrid response to sustained moderate drought stress reveals clues for improved management. Agronomy. 10(9). Article 1374. https://doi.org/10.3390/agronomy10091374.
DOI: https://doi.org/10.3390/agronomy10091374

Interpretive Summary: Shifts in climate patterns are predicted to increase the adverse effect of drought on corn yields in the future. Yield loss to drought stress can be mitigated by irrigation, but sufficiency of irrigation water supply is also a growing concern. Therefore, judicious management requires accurate estimation of the factors used to determine water application. This study was conducted to evaluate actual evapotranspiration, water use efficiency, and crop coefficients of corn with drought stress imposed at key stages in the growth cycle, and the effects of different rates of nitrogen fertilization. Two hybrids were tested and compared, standard and drought-tolerant. Evapotranspiration, crop water use, and yields were reduced for both hybrids under drought stress. Yields, crop water use efficiency, and irrigation water use efficiency were greater for the drought-tolerant hybrid across the conditions of the test. Drought stress reduced corn crop coefficients for both hybrids. The crop coefficients published in this paper are useful to researchers, academics, engineers, and producers for optimizing irrigation water use for corn production under drought conditions.

Technical Abstract: Crop water use efficiency (CWUE), irrigation water use efficiency (IWUE), basal crop coefficient (Kcb), and actual crop evapotranspiration (ETa) are essential parameters for accurate estimation of crop water requirement to prevent irrigation water waste. These parameters were evaluated by conducting three experiments using a drought-tolerant maize hybrid and a non-drought tolerant (‘standard’) maize hybrid receiving 50, 100, and 150% of the recommended optimal nitrogen (N) fertilizer rate and grown under well-watered conditions, drought stress from the 14 leaf collar maize phenological stage (V14) and the blister maize phenological stage (R2) to maize physiological maturity (R6). Across hybrids, ET¬a decreased with increased duration of drought stress. The drought-tolerant hybrid had 7 and 8% greater CWUE and IWUE, respectively, compared to the standard hybrid when drought stress began at V14. Mid-season Kcb was 1.08, 0.89, and 0.73 under well-watered conditions and when drought stress began at R2 and V14, respectively. These results reveal that (i) maize achieved more effective physiological acclimation with earlier exposure to drought stress, (ii) grain yield of the drought-tolerant hybrid was unchanged by earlier, compared to later, onset of drought despite a 10% decrease in ETa, and (iii) two phases of acclimation were identified: maize Kcb declined upon exposure to drought but stabilized as the crop acclimated.