Black Knot Unraveled: Phenotypic Characterization of Disease Resistance in Japanese Plums

Black knot (BK) disease, caused by <i>Apiosporina morbosa</i> (Schwein.) v. Arx, significantly afflicts Japanese plums (<i>Prunus salicina</i> L.), resulting in substantial economic losses due to its destructive invasion of branches and trunks. Phenotyping for disease severit...

Full description

Saved in:
Bibliographic Details
Main Authors: Chloe Shum, Wendy McFadden-Smith, Walid El Kayal, Jayasankar Subramanian
Format: Article
Language:English
Published: MDPI AG 2025-04-01
Series:Horticulturae
Subjects:
Online Access:https://www.mdpi.com/2311-7524/11/5/482
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1850257038496497664
author Chloe Shum
Wendy McFadden-Smith
Walid El Kayal
Jayasankar Subramanian
author_facet Chloe Shum
Wendy McFadden-Smith
Walid El Kayal
Jayasankar Subramanian
author_sort Chloe Shum
collection DOAJ
description Black knot (BK) disease, caused by <i>Apiosporina morbosa</i> (Schwein.) v. Arx, significantly afflicts Japanese plums (<i>Prunus salicina</i> L.), resulting in substantial economic losses due to its destructive invasion of branches and trunks. Phenotyping for disease severity is critical to understanding resistance and susceptibility across diverse genotypes. In this study, 200 Japanese plum trees from a mixed lineage breeding program were phenotyped for BK severity using a rating scale from 0 to 5. Trees were rated by two independent raters and repeated on a second day, in early spring 2023, before leaf emergence, for peak visibility. The rating system was designed to capture varying levels of infection, with 0 representing no symptoms and 5 indicating severe infection with major effects to the tree’s overall health. Compared to data from 2015 and 2018, there was a noticeable increase in the number of heavily diseased trees relative to symptom-free trees. In 2023, the proportion of completely resistant trees remained the same as in 2018, suggesting true resistance. Median scores were calculated from four independent ratings per tree, comprised of two individuals on two different days, minimizing individual biases. Additionally, inter-rater reliability was assessed using the weighted Kappa statistic, which yielded a value of 0.903, indicating strong agreement between raters. This phenotypic assessment provides a robust dataset for correlation with genetic markers and supports further breeding efforts aimed at developing BK-resistant cultivars.
format Article
id doaj-art-bb6b28af2e8542c39f2ccfe1f2ae87f5
institution OA Journals
issn 2311-7524
language English
publishDate 2025-04-01
publisher MDPI AG
record_format Article
series Horticulturae
spelling doaj-art-bb6b28af2e8542c39f2ccfe1f2ae87f52025-08-20T01:56:31ZengMDPI AGHorticulturae2311-75242025-04-0111548210.3390/horticulturae11050482Black Knot Unraveled: Phenotypic Characterization of Disease Resistance in Japanese PlumsChloe Shum0Wendy McFadden-Smith1Walid El Kayal2Jayasankar Subramanian3Plant Agriculture, Ontario Agricultural College, Vineland Campus, University of Guelph, Guelph, ON N1G 2W1, CanadaOntario Ministry of Agriculture, Food and Agribusiness (OMAFA), 4890 Victoria Avenue North, Vineland Station, ON L0R 2E0, CanadaFaculty of Food and Agricultural Sciences, American University of Beirut, Beirut 1107 2020, LebanonPlant Agriculture, Ontario Agricultural College, Vineland Campus, University of Guelph, Guelph, ON N1G 2W1, CanadaBlack knot (BK) disease, caused by <i>Apiosporina morbosa</i> (Schwein.) v. Arx, significantly afflicts Japanese plums (<i>Prunus salicina</i> L.), resulting in substantial economic losses due to its destructive invasion of branches and trunks. Phenotyping for disease severity is critical to understanding resistance and susceptibility across diverse genotypes. In this study, 200 Japanese plum trees from a mixed lineage breeding program were phenotyped for BK severity using a rating scale from 0 to 5. Trees were rated by two independent raters and repeated on a second day, in early spring 2023, before leaf emergence, for peak visibility. The rating system was designed to capture varying levels of infection, with 0 representing no symptoms and 5 indicating severe infection with major effects to the tree’s overall health. Compared to data from 2015 and 2018, there was a noticeable increase in the number of heavily diseased trees relative to symptom-free trees. In 2023, the proportion of completely resistant trees remained the same as in 2018, suggesting true resistance. Median scores were calculated from four independent ratings per tree, comprised of two individuals on two different days, minimizing individual biases. Additionally, inter-rater reliability was assessed using the weighted Kappa statistic, which yielded a value of 0.903, indicating strong agreement between raters. This phenotypic assessment provides a robust dataset for correlation with genetic markers and supports further breeding efforts aimed at developing BK-resistant cultivars.https://www.mdpi.com/2311-7524/11/5/482black knotJapanese plumdisease resistancefungal pathogen<i>Apiosporina morbosa</i>phenotyping
spellingShingle Chloe Shum
Wendy McFadden-Smith
Walid El Kayal
Jayasankar Subramanian
Black Knot Unraveled: Phenotypic Characterization of Disease Resistance in Japanese Plums
Horticulturae
black knot
Japanese plum
disease resistance
fungal pathogen
<i>Apiosporina morbosa</i>
phenotyping
title Black Knot Unraveled: Phenotypic Characterization of Disease Resistance in Japanese Plums
title_full Black Knot Unraveled: Phenotypic Characterization of Disease Resistance in Japanese Plums
title_fullStr Black Knot Unraveled: Phenotypic Characterization of Disease Resistance in Japanese Plums
title_full_unstemmed Black Knot Unraveled: Phenotypic Characterization of Disease Resistance in Japanese Plums
title_short Black Knot Unraveled: Phenotypic Characterization of Disease Resistance in Japanese Plums
title_sort black knot unraveled phenotypic characterization of disease resistance in japanese plums
topic black knot
Japanese plum
disease resistance
fungal pathogen
<i>Apiosporina morbosa</i>
phenotyping
url https://www.mdpi.com/2311-7524/11/5/482
work_keys_str_mv AT chloeshum blackknotunraveledphenotypiccharacterizationofdiseaseresistanceinjapaneseplums
AT wendymcfaddensmith blackknotunraveledphenotypiccharacterizationofdiseaseresistanceinjapaneseplums
AT walidelkayal blackknotunraveledphenotypiccharacterizationofdiseaseresistanceinjapaneseplums
AT jayasankarsubramanian blackknotunraveledphenotypiccharacterizationofdiseaseresistanceinjapaneseplums