Scholarship & Research
Permanent URI for this communityhttps://scholarworks.montana.edu/handle/1/1
Browse
2 results
Search Results
Item Tritrophic responses to signaling formulations sprayed in wheat stem sawfly-infested field plots(Montana State University - Bozeman, College of Agriculture, 2019) Caron, Christopher G.; Chairperson, Graduate Committee: Scott PowellThe wheat stem sawfly (Cephus cinctus Norton) is an economically important pest of wheat in the Northern Great Plains of North America. Producers and researchers are continuing to search for an effective management strategy. A combination of management tactics, such as host-plant resistance and biocontrol, may be the best method to suppress wheat stem sawfly (WSS) populations. My study examines whether direct toxicity, induced host-plant resistance, or the manipulation of tritrophic interactions, can be achieved through the application of signaling molecules in WSS-infested plots. The overall objective was to assess whether signaling molecules could be incorporated as a management tactic for WSS. Field experiments assessed whether aqueous applications of methyl jasmonate (MeJA), methyl salicylate (MeSA), and Actigard? influence WSS fitness, host-plant fitness, or the recruitment of natural enemies. Treatments were applied in WSS-infested plots for 3 consecutive weeks in both 2017 and in a second experiment in 2018. Wheat samples were collected before harvest and processed to assess parameters of infestation and parasitism. Plant growth and yield parameters were also recorded. The field trials suggested that MeJA and Actigard? induced significant changes that can impact tritrophic interactions in winter wheat. No effect was observed from the applications of MeSA. WSS fitness parameters decreased with applications of MeJA. MeJA treated plots had decreased infestation (2017), decreased larval weight (2018), and increased neonate mortality (2018). Actigard? treated plots had decreased larval weight and increased recruitment of clerid beetles (Phyllobaenus dubius Wolcott) (2017). Treatments of MeJA decreased stem height and grain weight, while treatments of Actigard? decreased grain weight in 2017. Although many of these findings were not consistent for both growing seasons, this study demonstrates the potential for these signaling molecules to manipulate the interactions between the WSS, or its host plant, and associated natural enemies in winter wheat.Item Evaluation of wheat stem sawfly‐resistant solid stem Qss.msub‐3BL alleles in hard red winter wheat(Wiley, 2023-01) Wong, Mei Ling; Bruckner, Philip L.; Berg, Jim E.; Lamb, Peggy F.; Hofland, Megan L.; Caron, Christopher G.; Heo, Hwa‐Young; Blake, Nancy K.; Weaver, David K.; Cook, Jason P.Host plant resistance provided by solid stems has been the most effective means for mitigating wheat stem sawfly (WSS) (Cephus cinctus Norton) damage in spring and winter wheat (Triticum aestivum L.). The solid stem trait originates from the spring wheat cultivar “Rescue” and is associated with a quantitative trait locus allele Qss.msub-3BL.b that explains the majority of the variation for stem solidness. Recently, a new Qss.msub-3BL solid stem allele, designated Qss.msub-3BL.c, was identified in the spring wheat cultivar “Conan”. It produces a solid stem phenotype early in plant development but dissipates during plant growth. The Qss.msub-3BL.c allele provides effective WSS resistance in spring wheat but has not been tested in winter wheat. To examine if the Qss.msub-3BL.c allele provides adequate WSS resistance in winter wheat, near-isogenic lines (NILs) were developed using marker-assisted backcrossing. This enabled comparisons between the hollow stem Qss.msub-3BL.a, solid stem Qss.msub-3BL.b and solid stem Qss.msub-3BL.c alleles for stem solidness, WSS resistance, and agronomic traits in Montana growing environments. Compared to the hollow stem allele, the NILs with the Qss.msub-3BL.c allele increased stem solidness and reduced WSS stem cutting. However, the Qss.msub-3BL.c allele resulted in lower solid stem scores and greater WSS stem cutting compared to the Qss.msub-3BL.b allele. Overall, these findings indicate that the Qss.msub-3BL.c allele failed to provide sufficient WSS resistance in the winter wheat backgrounds tested in this study.