Poster # 516

Fang Wang ^1,2, Ahmed Charif ^1,2, Tatiana Danilova ², Shaobin Zhong ³, Andrew Green ⁴, Katherine Frels ¹, Stephen Wegulo ⁵, Jeffrey Boehm Jr. ^2,1, and Xiwen Cai ^2,1
1. Department of Agronomy and Horticulture, University of Nebraska, Lincoln, NE 68583, USA
2. USDA-ARS, Wheat, Sorghum & Forage Research Unit, Lincoln, NE 68583, USA
3. Department of Plant Pathology, North Dakota State University, Fargo, ND 58108, USA
4. Department of Plant Sciences, North Dakota State University, Fargo, ND 58108, USA
5. Department of Plant Pathology, University of Nebraska, Lincoln, NE 68583, USA
Corresponding Author: PH: 402-326-4055; Email: xiwen.cai@usda.gov

Fang Wang

Fusarium head blight (FHB) may cause significant yield and quality losses of wheat, including Fusarium-damaged kernels (FDK) and accumulation of deoxynivalenol (DON) in seeds. Enhancing host resistance by exploring new resistance genes is the most cost-effective approach for FHB management. Here we report the marker-assisted introgression of Thinopyrum elongatum (2n=2x=14, EE)-derived FHB resistance gene Fhb7^The2 into adapted hard red spring wheat (HRSW) breeding lines for germplasm/variety development. Fhb7^The2 is a novel FHB resistance allele of Fhb7 originating from Thinopyrum species and has been transferred to ‘Chinese Spring’ wheat through a wheat-Th. elongatum 7B-7E translocation (7BS·7BL-7EL), which was released as ‘WGC002’. Fhb7^The2 confers Type II FHB resistance and may reduce DON accumulation, as previously reported. In addition, Fhb7^The2 is not associated with the linkage drag negatively impacting flour color from the Th. ponticum-derived Fhb7 allele, making it more desirable for breeding programs. Highly diagnostic sequence-tagged site (STS) and SNP-specific PCR allelic competitive extension (PACE) markers were developed to assist selection of Fhb7^The2 in FHB resistance breeding efforts and have been efficiently applied in the development of adapted FHB-resistant wheat breeding lines. Three HRSW breeding lines with favorable agronomic and end-use quality traits were selected as recurrent parents to cross with WGC002 for Fhb7^The2 introgression using a marker-assisted backcrossing (MABC) breeding pipeline. Four backcrosses utilizing the PACE markers were conducted to develop Fhb7^The2 introgression lines. The Fhb7^The2 introgression lines and their recurrent parents were evaluated in the FHB nurseries at Lincoln, NE, and Fargo, ND in 2023 and rated for FHB severity (SEV), incidence (INC), and FDK. Disease evaluation results indicated that the HRSW introgression lines with Fhb7^The2 had significantly lower (P < 0.05) SEV and FDK than their recurrent parents. In addition, kernels of the introgression lines and their recurrent parents harvested from the FHB nurseries are presently being tested for DON accumulation. Thus, Fhb7^The2 enhances and diversifies FHB resistance in wheat. Moreover, the Th. elongatum 7EL segment containing Fhb7^The2 is inherited as a single locus, which makes the MABC breeding highly effective for Fhb7^The2 introgression into other wheat backgrounds.