Sclerotinia stem rot (SSR), is caused by the soilborne fungal pathogen Sclerotinia sclerotiorum and consistently ranks in the top ten diseases that reduce soybean yields in the United States. The interaction of environmental conditions in the canopy including light, temperature, and humidity favor SSR development. The impact of soybean canopy architecture on these conditions and SSR development is an understudied area of research. If identified, plant architecture traits to reduce disease development may be useful for future resistance breeding efforts, especially when combined physiological resistance.
This project aims to define relationships between canopy architecture and Sclerotinia development, to provide another, underexplored consideration for disease resistance breeding to avoid yield losses from SSR.

GOAL: Define relationship between canopy architecture and SSR development to improve SSR avoidance and management.
Obj. 1) Characterize architectural traits and canopy closure of select lines in the field (continuing)
Obj. 2) Measure microclimate conditions along with apothecia and SSR development (continuing)

Obj. 3) Assess disease development in current, commercial varieties of varied architectures.

Obj. 4) Evaluate the interaction of architecture and chemical management for disease control.

? Results will be presented at seminars and regional (Prairie Grains, Minnesota Ag Expo) and
national meetings.
? Peer-reviewed research publications will be developed.
? A research education and outreach opportunity will be available to students in my lab who are
assisting with the project. The next generation of soybean researchers will be trained in grower-
driven research.
? New breeding opportunities will be explored through enhancing disease escape with plant
architectural traits and candidate lines for breeding will be identified.
? Identification of lines with unique branching phenotypes can lead to candidates for quantitative
trait loci (QTL) studies to identify genes related to branching phenotypes and disease resistance.
? Information will be generated on the influence of commercial variety architecture on disease.
? Collaborations between researchers of various departments and universities will build bridges of
expertise in soybean research to enhance each other’s work in soybean improvement.

Updated August 31, 2024:

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Disease management options for Sclerotinia stem rot are limited, and genetic resistance is one of
the most effective lines
of defense against any plant disease. This project will aim to improve resistance screening methods
by developing a collection of S. sclerotiorum isolates that are typical of Minnesota, with a
representative ability to cause disease symptoms in soybean. Additionally, uniform and reliable
disease pressure developed in the field will allow me to share reliable data with growers due to
consistent SSR disease pressure for variety and experimental trials. Finally, the development of
SSR disease is very dependent on environmental conditions. Plant architecture may play an important
role in creating conditions that are ideal for disease development. We will evaluate the importance
of plant architectural traits for disease development. This work may lead to opportunities to
further improve soybean resistance to SSR by

breeding for architectural traits that discourage SSR development and improve yield. Ultimately, we
aim to explore
genetic/architectural management tools for growers to use in SSR-infested fields to avoid yield
losses. Results will be provided to growers via outreach materials and at grower meetings.
A student will focus on the objectives described in this proposal for their master’s thesis.
Through this project, students will learn more about research in soybeans and will develop as
budding experts to assist with future production challenges through science.
Lastly, this project is collaborative and uses resources from researchers in different institutions
and departments. These collaborative relationships will provide enhanced idea generation and pooled
resources for future projects in Minnesota
soybeans.