USWBSI Abstract Viewer

2023 National Fusarium Head Blight Forum


Variety Development and Host Resistance (VDHR)

Poster # 507

Use of Modified Backcrosses for the Incorporation of Fhb7 in Winter Wheat Germplasm

Authors & Affiliations:

Bhanu Dangi1 and Francois Marais1
1. North Dakota State University, The Department of Plant Sciences, Fargo, ND
Corresponding Author: Bhanu Dangi, bhanu.dangi@ndsu.edu

Corresponding Author:

Bhanu Dangi
bhanu.dangi@ndsu.edu

Abstract:

Fusarium head blight (FHB) is a floral disease of cereal crops that decreases grain yield and quality and it is best controlled with the use of host resistance. However, wheat resistance to FHB has complex quantitative inheritance and no genotypes have been found to be absolutely resistant. Consequently, discovery, introgression, and pyramiding of FHB resistance genes have been the focus of wheat breeding programs worldwide. Recently, the FHB resistance gene, Fhb7, has been transferred via a 7BS.7BL-7E translocation from Thinopyrum elongatum to common wheat cultivar Chinese Spring. This study utilized the F1 between ND Allison and a resistant accession, XWC14-255-3-1, to initiate transfer of Fhb7 through modified backcrosses to diverse hard red winter wheat (HRWW) genotypesThe first backcross was made to four different HRWW cultivars. To confirm the presence of the translocation and the utility of its dominant STS marker (WGC2315), 81 B1F1 genotypes and parental controls were genotyped with the Illumina 90K SNP array and marker WGC2315. WGC2315 was detected in 36 B1F1 plants and co-segregated with three SNP loci mapped to the reported region at the distal end of chromosome 7B, thus validating both the location and effectiveness of the STS marker. A single B1F1 heterozygote for Fhb7 with superior phenotype was selected for a second backcross to four HRWW parents, one of which was an Fhb1 homozygote. A third and final backcross was made to another five diverse HRWW parents to produce B3F1. Two final backcross parents had no known FHB resistance QTL, while the remaining three likely had “native” FHB resistance from ND Noreen. The latter three parents were each homozygous for markers of both Qfhb.rwg-5A.1 and Qfhb.rwg-5A.2. The B3F1 were tested for the presence of Fhb7 using marker WGC2315. B3F2 segregating for the Fhb7 marker were planted for a final marker analysis. A recently published codominant STS marker set will be used to test all backcross parents and 322 B3F2 individuals for the presence of Fhb7. In addition, the segregates and controls will be evaluated for FHB type II resistance (greenhouse) and tested with additional markers for Fhb1Qfhb.rwg-5A.1Qfhb.rwg-5A.2 and certain leaf, stem, and stripe rust resistance genes. The combined data will be used to identify the promising B3F2 plants from which potentially useful resistance gene pyramids can be developed. Promising families will be used for ongoing early-generation inbreeding and breeding parents will be selected for use in upcoming routine breeding crossing blocks.


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