Genetic loci resistant to soybean southern stem canker in Tracy-M and its progeny
- 1Institute of Plant Breeding, Genetics, and Genomics, and Department of Crop and Soil Sciences, University of Georgia , Athens, GA 30602 ,
- 2Department of Plant Pathology, University of Georgia , Griffin, GA 30223 ,
Abstract
Southern stem canker (SSC), caused by Diaporthe aspalathi, is a major soybean disease causing yield losses of up to 80%. Genetic resistance is the most effective and sustainable strategy for managing SSC. “Tracy-M” is a cultivar with broad resistance to D. aspalathi isolates; however genomic location of the resistance is unknown. To determine the genetic basis of SSC resistance in Tracy-M and its derived progeny, two Tracy-M-derived lines, D85-10404 and D85-10412, were each crossed with a common susceptible parent, G81-2057, to develop recombinant inbred line (RIL) populations. Quantitative Trait Locus (QTL) sequencing (QTL-seq) and composite interval mapping (CIM) identified a common major QTL on chromosome (Chr) 2 in both lines corresponding to Rdm1 locus defined from a previous genetic study. Additionally, second QTL located on Chr 17 (Rdm2 locus) was only detected in the D85-10412-derived RIL population. To validate Tracy-M-derived resistance, an F2:3 population from G00-3213 × Tracy-M was developed. Bulked segregant analysis (BSA) and CIM identified a major QTL on Chr 14, overlapping the previously reported Rdm3 locus in “Crockett” and PI 398469, while Rdm1 was not detected, suggesting genetic background effects. Kompetitive allele-specific PCR (KASP) markers were developed to facilitate selection of Rdm1, Rdm2, and Rdm3 resistance alleles in soybean breeding programs.
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BibTeX
@article{widyawan2026genetic,
title = {{Genetic loci resistant to soybean southern stem canker in Tracy-M and its progeny}},
author = {M Habib Widyawan and James W Buck and Zenglu Li},
journal = {G3: Genes, Genomes, Genetics},
year = {2026},
month = oct,
doi = {10.1093/g3journal/jkag278},
url = {https://academic.oup.com/g3journal/advance-article/doi/10.1093/g3journal/jkag278/8907168},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Genetic loci resistant to soybean southern stem canker in Tracy-M and its progeny
AU - M Habib Widyawan
AU - James W Buck
AU - Zenglu Li
PY - 2026
DA - 2026/10/10
JO - G3: Genes, Genomes, Genetics
DO - 10.1093/g3journal/jkag278
UR - https://academic.oup.com/g3journal/advance-article/doi/10.1093/g3journal/jkag278/8907168
AB - Southern stem canker (SSC), caused by Diaporthe aspalathi, is a major soybean disease causing yield losses of up to 80%. Genetic resistance is the most effective and sustainable strategy for managing SSC. “Tracy-M” is a cultivar with broad resistance to D. aspalathi isolates; however genomic location of the resistance is unknown. To determine the genetic basis of SSC resistance in Tracy-M and its derived progeny, two Tracy-M-derived lines, D85-10404 and D85-10412, were each crossed with a common susceptible parent, G81-2057, to develop recombinant inbred line (RIL) populations. Quantitative Trait Locus (QTL) sequencing (QTL-seq) and composite interval mapping (CIM) identified a common major QTL on chromosome (Chr) 2 in both lines corresponding to Rdm1 locus defined from a previous genetic study. Additionally, second QTL located on Chr 17 (Rdm2 locus) was only detected in the D85-10412-derived RIL population. To validate Tracy-M-derived resistance, an F2:3 population from G00-3213 × Tracy-M was developed. Bulked segregant analysis (BSA) and CIM identified a major QTL on Chr 14, overlapping the previously reported Rdm3 locus in “Crockett” and PI 398469, while Rdm1 was not detected, suggesting genetic background effects. Kompetitive allele-specific PCR (KASP) markers were developed to facilitate selection of Rdm1, Rdm2, and Rdm3 resistance alleles in soybean breeding programs.
SN - 2160-1836
ER -