Can pyraclostrobin and epoxiconazole protect conventional and stay-green maize varieties grown under drought stress?

PLoS One. 2019 Aug 20;14(8):e0221116. doi: 10.1371/journal.pone.0221116. eCollection 2019.

Abstract

Risks associated with drought are increasing and are a global problem. Therefore, there is a need for new solutions for the safe production of food, while maintaining respect for the environment. Fungicides are designed to protect maize plants against disease, but some of the active substances used in preparations can also promote plant growth, which is known as the 'physiological effect'. However, there is a paucity of information as to how some of the 'new generation' fungicides act in stimulating grain yield in plants under abiotic stress, especially drought. Therefore, the effects of these products on conventional and stay-green maize varieties need to be better understood in order to reduce losses caused by droughts and to maximize production. In this study, the effect of a pyraclostrobin + epoxiconazole fungicide preparation on maize plants was evaluated at different times after spraying; during induced drought conditions and again during the regeneration process of the plants. The preparation was applied to 'KWS 1325' (conventional) and 'Ambrosini' (stay-green) varieties at the recommended dose, three times in greenhouse conditions. Plant gas exchange, plant water use efficiency, chlorophyll fluorescence and fresh and dry plant biomass were evaluated. The pyraclostrobin + epoxiconazole preparation increased stomatal conductance and photosynthesis intensity in the 'Ambrosini' plants. When maintained under a high light intensity, the variety used increased efficiency and exchanged excessive energy in the form of thermal energy to protect the maize leaf from light-induced damage under drought stress. Plant photosynthetic efficiency (ETR and Yield parameters) during drought stress and after regeneration was significantly higher in treated plants than in the controls. Thus, the beneficial effects on the physiology of the maize varieties grown under drought stress from the fungicide application are significant for farmers and growers.

MeSH terms

  • Crop Protection / methods*
  • Droughts*
  • Epoxy Compounds / pharmacology
  • Fungicides, Industrial / pharmacology*
  • Photosynthesis / drug effects
  • Plant Stomata / drug effects
  • Plant Stomata / physiology
  • Stress, Physiological / drug effects*
  • Strobilurins / pharmacology
  • Triazoles / pharmacology
  • Zea mays / drug effects*
  • Zea mays / physiology

Substances

  • Epoxy Compounds
  • Fungicides, Industrial
  • Strobilurins
  • Triazoles
  • pyrachlostrobin
  • epoxiconazole

Grants and funding

The authors received no specific funding for this work. Hazem M. Kalaji is employed by White Hill Company. White Hill Company provided support in the form of salary for author MHK, but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific role of this author is articulated in the ‘author contributions’ section.