Assessing the impact of plant growth regulators on anther retention and Fusarium head blight in spring wheat (Triticum aestivum L.) infected by Fusarium graminearum in field conditions

Abstract

Fusarium head blight (FHB) resistance in wheat is often associated with undesirable agronomic traits such as tall plant height and a propensity for lodging. Plant height in wheat is genetically controlled by some semi-dwarfing alleles that alter the plant's sensitivity to gibberellins (GAs). The presence of semi-dwarfing alleles increases the frequency of anther retention, which may contribute to FHB susceptibility by providing an initiation site for infection. The application of plant growth regulators (PGRs) may enable farmers to grow the most resistant cultivars while controlling plant height to minimize lodging risk. In this study, five spring wheat cultivars that differed in level of FHB resistance, height, and semi-dwarfing alleles were tested to determine the effect of PGRs, specifically Manipulator™ and Ethrel™, on plant height, anther retention, and FHB resistance level and the interactions between them in Winnipeg and Carman, Manitoba in 2019 and 2020. Combined field results showed that Ethrel™ significantly reduced plant height. Both PGRs did not affect the anther retention or FHB resistance levels of the tested cultivars under dry conditions. There were significant interactions between variables, but they were relatively small compared to the main treatment and cultivars. Based on the results of this study, producers could benefit from the higher levels of FHB resistance often associated with tall cultivars and use PGRs to manage plant height and lodging without increased risk of FHB.