Paper · 2026 · The Plant Phenome Journal

Phenotypic scoring of canola blackleg severity using machine learning image analysis

Qiao Hu; Sarah Anderson; Stuart Gardner; et al.

4
claims
8
verbatim quotes
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citations
4
research areas
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Open access · cc-by-nc-nd

Abstract

Abstract Canola blackleg is a fungal disease that causes significant yield loss and plant death of infected canola ( Brassica napus L., Brassica rapa L ., Brassica juncea L .) fields worldwide. One of the most effective methods for controlling blackleg is through the cultivation of resistant varieties. Consequently, quantitative scoring of blackleg disease severity of infected plants is a key metric for identifying and selecting resistant varieties. Traditionally, blackleg severity is scored by expert raters who evaluate disease in stem cross sections using established rating scales and reference images; however, human raters are expensive and inconsistent in their scoring. Here, we introduce a machine learning algorithm based on deep learning models that can score blackleg severity from cross‐section images of infected plants. We find that expert ratings are inconsistent across raters and across years for the same rater, creating substantial noise in resistance ratings. Meanwhile, our trained machine learning model performs more consistently than the median rater while maintaining a similar heritability as expert raters for the blackleg resistance trait. This model can be used to standardize blackleg resistance scoring across locations and years to improve canola breeding outcomes across affected regions.

Abstract from the paper’s OpenAlex record; open copy licensed cc-by-nc-nd. Read at the source ↗

The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.

Claims 4

Observationobservedoriginal resultmeasured

Claim · model-written summary

Expert blackleg severity ratings were inconsistent across raters and across years for the same rater.

Outcome
expert ratingse2
Qualifier
across raters and across years for the same ratere2

Not reportedDirection

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Brassica napus var. napus
Brassica napus var. napus · Taxoncontri from Yonezawa-Shi, Yamagata, Japan · CC BY-SA 2.0 · Wikimedia Commons ↗

Verbatim

e1

“infected canola ( Brassica napus L., Brassica rapa L ., Brassica juncea L .)”

✓ located verbatim in the source · abstract, characters 99–175 · show in text ↑
e2

“expert ratings are inconsistent across raters and across years for the same rater”

✓ located verbatim in the source · abstract, characters 853–934 · show in text ↑
Method / resourceobservedoriginal resultpositivemeasured

Claim · model-written summary

The machine learning model scored blackleg severity more consistently than the median rater.

Outcome
performs more consistentlye2
Direction
more consistentlye2
Comparator
median ratere2

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Brassica napus var. napus
Brassica napus var. napus · Taxoncontri from Yonezawa-Shi, Yamagata, Japan · CC BY-SA 2.0 · Wikimedia Commons ↗

Verbatim

e1

“infected canola ( Brassica napus L., Brassica rapa L ., Brassica juncea L .)”

✓ located verbatim in the source · abstract, characters 99–175 · show in text ↑
e2

“our trained machine learning model performs more consistently than the median rater”

✓ located verbatim in the source · abstract, characters 997–1080 · show in text ↑
Method / resourceobservedoriginal resultno effectmeasured

Claim · model-written summary

The machine learning model maintained a heritability for blackleg resistance similar to that of expert raters.

Outcome
heritabilitye2
Direction
similare2
Qualifier
blackleg resistance traite2
Comparator
expert raterse2

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Brassica napus var. napus
Brassica napus var. napus · Taxoncontri from Yonezawa-Shi, Yamagata, Japan · CC BY-SA 2.0 · Wikimedia Commons ↗

Verbatim

e1

“infected canola ( Brassica napus L., Brassica rapa L ., Brassica juncea L .)”

✓ located verbatim in the source · abstract, characters 99–175 · show in text ↑
e2

“while maintaining a similar heritability as expert raters for the blackleg resistance trait”

✓ located verbatim in the source · abstract, characters 1081–1172 · show in text ↑
Recommendationauthor interpretationoriginal resultbasis n/a

Claim · model-written summary

The model should be used to standardize blackleg resistance scoring across locations and years to improve canola breeding.

Outcome
blackleg resistance scoringe2
Qualifier
across locations and yearse2

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Brassica napus var. napus
Brassica napus var. napus · Taxoncontri from Yonezawa-Shi, Yamagata, Japan · CC BY-SA 2.0 · Wikimedia Commons ↗

Verbatim

e1

“infected canola ( Brassica napus L., Brassica rapa L ., Brassica juncea L .)”

✓ located verbatim in the source · abstract, characters 99–175 · show in text ↑
e2

“This model can be used to standardize blackleg resistance scoring across locations and years to improve canola breeding outcomes across affected regions”

✓ located verbatim in the source · abstract, characters 1174–1326 · show in text ↑