Document Type

Thesis - Open Access

Award Date

2023

Degree Name

Master of Science (MS)

Department / School

Agronomy, Horticulture, and Plant Science

First Advisor

Madalyn Shires

Abstract

Roughly 50% of South Dakota cropland is under the practice of no-till, with large increases in acres of no-till in the last 20 or so years. No-till is beneficial for Great Plains states, such as South Dakota, as soil residues are withheld. Residues are shown to increase soil health through retention of moisture and increase of microorganisms, but residues can serve as a source of inoculum for fungal pathogens that can overwinter on them. As wheat is one of the most important food crops in the world, it is important to protect this vital crop from diseases. Diseases of wheat can reduce yields by a minimum of 20 percent on a global basis. Some of the most common wheat pathogens that affect plants are fungal pathogens, including leaf rusts, stripe rust, stem rusts, Stagonospora nodorum blotch, Septoria tritici blotch, and tan spot. These diseases were evaluated in seven different varieties (‘Draper’, ‘Ideal’, ‘Redfield’, ‘Thompson’, ‘Expedition’. ‘Wesley’, and ‘Oahe’) and four different residue amounts (20%, 40%, 60%, and 80% ground cover) to determine the importance of choosing a disease resistant variety and the effect of residue amounts on pathogen development and yield. The varieties were chosen due to their differences in tolerance and susceptibility to the pathogens, and the residue amounts were chosen to encompass a wide range of tillage/non-tillage systems. Results from this study indicate that there are multiple different spot pathogens present in South Dakota with the variety ‘Draper’ having significantly higher disease amounts in 2021. In 2022, the most disease amounts were seen on ‘Expedition’ which was susceptible/unrated for all leaf spot pathogens. ‘Expedition’ also had the greatest amount of stripe rust in 2021. The residue amounts were also shown to have a significant effect on disease development. The higher residue levels (60% and 80%) were often significantly higher in disease than the lower levels (20% and 40%). This study was done to establish a baseline for the types of diseases present in South Dakota wheat and to understand the effects that residues have on wheat production and disease development.

Library of Congress Subject Headings

Wheat -- Diseases and pests -- South Dakota.
Wheat -- Residues.
Wheat -- Varieties.
Fungal diseases of plants.

Publisher

South Dakota State University

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Rights Statement

In Copyright