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ARS Home » Southeast Area » Stoneville, Mississippi » Crop Genetics Research » Research » Publications at this Location » Publication #403789
Research Project: Evaluation and Development of Improved Soybean Germplasm, Curation of USDA Accessions and Regional Evaluations of New Genotypes

Location: Crop Genetics Research

Title: Phenotypic evaluation of soybean genotypes for their reaction to a Mississippi isolate of Phakopsora pachyrhizi causing soybean rust

Author
item Li, Shuxian
item Smith, James - Rusty

Submitted to: Plants
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/24/2023
Publication Date: 4/27/2023
Citation: Li, S., Smith, J.R. 2023. Phenotypic evaluation of soybean genotypes for their reaction to a Mississippi isolate of Phakopsora pachyrhizi causing soybean rust. Plants. 12-1797:1-14. https://doi.org/10.3390/plants12091797.
DOI: https://doi.org/10.3390/plants12091797

Interpretive Summary: Soybean rust is one of the most important foliar diseases of soybean, with the potential to cause major economic damage to global and U.S. soybean production. Determining the reactions of current soybean lines to the causal pathogen is an important step towards developing improved varieties for farmers with resistance to soybean rust. In this study, 54 diverse soybean lines with both known and unknown resistance genes (designated Rpp) were tested for their reactions to the SBR pathogen using a strain collected from Mississippi. PI 567102B (Rpp6) had the lowest disease severity score and was the most resistant line. Four soybean lines (RN06-32-1(7-b, GC 00138-29, G01-PR16, and GC 84051-9-1) had resistant reactions with significantly lower disease severity than three of the six resistant checks PI 230970 (Rpp2), PI 462312 (Rpp3), and PI 459025B (Rpp4), with G01-PR16 being publicly available through the Germplasm Resources Information Network (GRIN). This research provides new information about reactions of different soybean lines to the soybean rust pathogen from Mississippi, thereby aiding breeders in developing cultivars resistant to soybean rust.

Technical Abstract: Soybean rust (SBR), caused by Phakopsora pachyrhizi Syd. & P. Syd., is one of the most important foliar diseases of soybean. SBR has the potential to cause major economic damage to global and U.S. soybean production. Analysis of reactions of soybean genotypes to P. pachyrhizi is an important step towards breeding for resistance to SBR. Fifty-four diverse soybean genotypes with both known and unknown Rpp resistance genes were tested for their reactions to a Mississippi P. pachyrhizi isolate. PI 567102B (Rpp6) had a near immune reaction, with the lowest disease severity score and no sporulation. Among 17 genotypes with resistant incomplete- resistant reddish-brown (RB) reactions, eight were improved breeding lines, which are available to researchers through material transfer agreements (MTAs). Thirty-six genotypes had the susceptible TAN reaction. Four soybean lines (RN06-32-1(7-b, GC 00138-29, G01-PR16, and GC 84051-9-1) had RB reactions and significantly lower SBR severity and sporulation than three of the six resistant checks; PI 230970 (Rpp2), PI 462312 (Rpp3), and PI 459025B (Rpp4). G01-PR16 is a publicly released germplasm. This research provides new information about reactions of different soybean genotypes to a midsouthern USA isolate of P. pachyrhizi and thereby aids in breeding for resistance to SBR.