Theses and Dissertations at Montana State University (MSU)
Permanent URI for this collectionhttps://scholarworks.montana.edu/handle/1/733
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Item Role of crop fertility and seed treatments in managing fusarium root rot of lentil (Lens culinaris Medikus) in the northern Great Plains(Montana State University - Bozeman, College of Agriculture, 2021) Atencio, Sydney Christine; Chairperson, Graduate Committee: Perry Miller and Mary Burrows (co-chair)Lentil is a relatively new but economically important crop for the state of Montana, along with surrounding states in the northern Great Plains. Comparatively little is known about the basic fertility of lentil, and importance of inoculant type on lentil. Additionally, the rise of pulse crop acres in the northern Great Plains, has given rise to root rot pathogens, such as Fusarium root rot. Fusarium root rot of pulses, has a wide host range, limiting the efficacy of rotation in its management. This research is comprised of two main studies. Field trials occurred at sites in Bozeman, Havre, Moccasin, and Sidney in 2019 and 2020. The objective of chapter two was to evaluate the effect of rhizobial inoculant formulations (granular vs. seed-coat/peat-powder) and nutrient additions (potassium, sulfur, and a micronutrient fertilizer), on lentil establishment, growth, seed protein, and yield. For chapter two, in six of eight site-years there was no yield difference between inoculant types. Applications of sulfur (S) fertilizer increased yield at three of eight site-years by an average of 303 kg ha-1 (17%) compared to treatments without S. Results from this study further suggest the importance of S fertilization for lentil. The objective for chapter three was to evaluate seed treatments' ability to control Fusarium root rot on lentil establishment, growth, disease severity and yield. In three of eight site-years, the inoculated control had a relatively high disease severity compared to other seed treatments. In general, treatment responses varied across site-year due to low disease pressure. Additionally, F. graminearum and F. oxysporum were isolated at a high frequency from control plots at sites in 2019. Data from 2020 is pending.Item Pest management challenges and climate change in water limited winter wheat agroecosystems in southwestern Montana(Montana State University - Bozeman, College of Agriculture, 2020) Nixon, Madison Grace; Chairperson, Graduate Committee: Fabian D. MenalledDryland winter wheat production is influenced by many environmental factors including climate, disease, and resource availability. In Montana, Bromus tectorum (cheatgrass) and Fusarium pseudograminearum (a fungus causing root crown rot) are major winter wheat pests; reducing yield and grain quality. However, little is known how climate change and resource availability impact winter wheat, B. tectorum, and F. pseudograminearum individually as well as their multi-trophic interactions. Thus, this research aimed to 1) Determine the susceptibility of B. tectorum to F. pseudograminearum and assess how CO 2 and nitrogen impact their growth, and 2) Evaluate how elevated temperature, reduced precipitation, and plant competition impact winter wheat and B. tectorum growth and reproduction. Utilizing growth chambers, high and low nitrogen treatments, fungal inoculated and uninoculated treatments, and ambient and elevated CO 2 treatments, Bromus tectorum was found to be a host of F. pseudograminearum, and the fungus significantly reduced root, shoot and total biomass, as well as primary physiological processes of B. tectorum. Fusarium pseudograminearum infection was not impacted by nitrogen or CO 2 level. Low nitrogen increased emergence and root production early on, while high nitrogen increased shoot production at later growth stages. Low nitrogen also improved stomatal conductance and transpiration rate. High CO 2 increased B. tectorum root, shoot, and biomass production, as well as intercellular CO 2. An interaction between ambient CO 2 and low nitrogen resulted in the greatest shoot relative growth rate between the first and second harvest. Field tests, using three climate treatments (ambient, increased temperature, reduced precipitation with increased temperature) and three plant competition levels (monoculture winter wheat, monoculture B. tectorum, and biculture of the two), found that for both winter wheat and B. tectorum monocultures, ambient and warmer climates produced similar yields and biomass, respectively, whereas the drier with warmer treatment reduced these factors. Additionally, B. tectorum presence increased winter wheat grain protein. A quadratic interaction model of winter wheat yield as a function of B. tectorum biomass by climate treatment suggests that at low to moderate B. tectorum biomass levels, winter wheat yield was negatively impacted by the warmer and drier treatment, whereas ambient and warmer treatment results were similar.