Paclobutrazol improves surface water use efficiency by regulating allometric trait behavior in maize.

Area of Science:

• Agricultural Science
• Plant Physiology
• Drought Stress Management

Background:

• The role of Paclobutrazol (PBZ) in maize drought management is not well understood.
• Maize root traits are crucial for surface water management and drought resilience.

Purpose of the Study:

• To investigate the effect of PBZ on maize root traits and physiological processes under early and terminal deficit irrigation (EDI and TDI).
• To demonstrate the implication of allometric and root parameters in improving water use efficiency (WUE) for soil surface irrigation management in maize.

Main Methods:

• Imposed EDI and TDI with or without PBZ on DKC-9144 and PG-2475 maize varieties over three years.
• Measured allometric parameters (stem height, diameter, leaf area) and root traits.
• Analyzed physiological processes, gene expression (ZmRTCL, ZmRTCS, ZmARF34), and WUE using correlation and structural equation modeling.

Main Results:

• Increased lateral roots and root density in DKC-9144 improved water absorption during EDI.
• PBZ and EDI elevated expression of genes related to root initiation.
• TDI reduced WUE, associated with decreased stem thickness and leaf area; brace root surface area positively contributed to WUE under TDI with PBZ.

Conclusions:

• Specific root traits and their association with allometric parameters are vital for enhancing maize WUE, especially in the DKC-9144 variety.
• PBZ can be a valuable tool for improving maize drought tolerance and water management strategies.