Poster # 503 View Poster

Charlotte Brault ¹, Emily J. Conley ¹, Andrew C. Read ^1,2, Harsimardeep S. Gill ¹, Sarah Blecha ², Andrew J. Green ³, Karl D. Glover ⁴, Jason P. Cook ⁵, Ruth Dill-Macky ⁶, Jason Fiedler ⁷, James Anderson ¹
1. Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, MN 55108, USA
2. USDA-ARS, Plant Science Research Unit, St. Paul, MN 55108, USA
3. Department of Plant Sciences, North Dakota State University, Fargo, ND 58102, USA
4. Agronomy, Horticulture, and Plant Science Department, South Dakota State University, Brookings, SD 57007, USA
5. Plant Sciences and Plant Pathology Department, Montana State University, Bozeman, MT 59717, USA
6. Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108, USA.
7. USDA-ARS Cereal Crops Improvement Research Unit, Edward T. Schafer Agricultural Research Center, Fargo, ND 58102, USA
Corresponding Author: Charlotte Brault, cbrault@umn.edu

Brault, Charlotte

cbrault@umn.edu

There has been considerable work on increasing the genetic resistance to Fusarium head blight (FHB) in hard red spring wheat. Harnessing the phenotypic data from uniform regional nurseries, the genetic gain over the last 30 years was assessed for three FHB-related traits, namely disease index, visual scabby kernels, and deoxynivalenol concentration. Specifically, two nurseries were compared: the uniform regional nursery (URN), used to test variety release candidates with good agronomic qualities, and the uniform regional scab nursery (URSN), used to facilitate the phenotyping of FHB resistance and to exchange germplasm among the cooperating breeding programs. The objective of the study was three-fold: (i) studying the frequency of the major FHB-related quantitative trait locus (QTL) Fhb1, (ii) assessing the genetic gain for three FHB traits, and (iii) estimating the effect of this QTL on FHB and agronomic traits. Within these objectives, a comparison was made between the two nurseries. We showed that FHB resistance has increased significantly over the years for FHB-related traits, with a higher rate for the initially more susceptible URN materials. More recently, there has been little difference in the susceptibility level between the two nurseries. The frequency of the Fhb1 resistance allele has dramatically increased in frequency over the years, from 0% in 1995 to 40% in 2024 for the URN nursery. We observed a higher frequency of the resistance allele in the URSN compared to the URN nursery, but the differences tended to diminish over time. The Fhb1 resistance allele was significantly associated with increased FHB resistance for the three traits, with up to a 39% decrease for the disease index trait. We tested the effect of Fhb1 on agronomic traits using phenotypic data from the URN dataset and found that there was no detrimental association between the presence of resistance alleles and important agronomic traits. This work underscores progress achieved through breeding, likely due to a successful transfer of resistance alleles from the URSN to the URN material.

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