Could Canola Canopy Architecture Affect Pathogen Infection by Impacting Flower Accumulation on Branches?

Area of Science:

• Agricultural Science
• Plant Pathology
• Computational Biology

Background:

• Sclerotinia sclerotiorum causes significant yield loss in canola (Brassica napus), primarily through stem rot originating from infected fallen flowers.
• Canopy architecture's role in flower accumulation and subsequent Sclerotinia infection is not well understood.
• Infected flowers accumulating on branches serve as a crucial inoculum source for stem infections.

Purpose of the Study:

• To investigate the impact of varying canola canopy architecture on Sclerotinia infection rates via flower fall.
• To model the interplay between plant structure, wind conditions, and disease spread.
• To identify architectural traits that could mitigate Sclerotinia stem rot.

Main Methods:

• Development of a static structural model integrated with a novel flower fall model considering wind effects.
• Simulation of canola fields with different branching architectures (upright vs. outstretched).
• Analysis of flower accumulation patterns and infection incidence under various simulated wind conditions.

Main Results:

• Upright canola architectures led to increased Sclerotinia infection due to greater flower accumulation above axils.
• Outstretched branching architectures reduced infection by positioning fewer flowers above axils.
• No single architecture provided consistent protection across all tested wind conditions.

Conclusions:

• Canola plant architecture significantly influences Sclerotinia infection dynamics.
• Manipulating plant architecture, such as by reducing planting density or through breeding, can be a cost-effective strategy to reduce disease.
• Findings have potential applications for other crops where infected flowers cause stem disease.