Poster # 517

Navin Shrestha^1,2, Ahmed Charif^1,2, Fang Wang^1,2, Tatiana Danilova¹, Yueqiang Leng³, Shaobin Zhong³, Zhao Jin⁴, Deanna Funnell-Harris¹, Katherine Frels², Stephen Wegulo⁵, Andrew Green⁴, Steven Xu⁶, and Xiwen Cai^1,2
1. USDA-ARS, Wheat, Sorghum & Forage Research Unit, Lincoln, NE 68583, USA
2, Department of Agronomy and Horticulture, University of Nebraska, 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
6. USDA-ARS, Crop Improvement and Genetics Research Unit, Western Regional Research Center, Albany, CA 94710, USA
Corresponding Author: Ph: 402-326-4055; Email: xiwen.cai@usda.gov

Shrestha, Navin

nshrestha6@nebraska.edu

Fusarium head blight (FHB) poses a significant threat to wheat production, severely affecting grain yield, grade, and end-use quality. Developing and utilizing host resistance remains the most effective and sustainable approach to manage the disease. However, the limited availability of resistance genes that can be effectively integrated into high-yielding wheat cultivars is one of the major hurdles. The primary objective of this study was to incorporate Thinopyrum elongatum-derived resistance gene Fhb7^The2 into major FHB resistance sources, including Sumai 3, Frontana, and PI 277012 for the development of germplasm with enhanced resistance. To achieve this, Sumai 3, Frontana, and PI 277012 were hybridized with the Fhb7^The2 source line WGC002 (PI 702949). The F₁ hybrids of these three crosses were backcrossed four times to their respective recipient parents (i.e. Sumai 3, Frontana, and PI 277012) through a marker-assisted backcrossing breeding pipeline. Fhb7^The2-specific PACE markers were used to select the progeny containing Fhb7^The2 in each backcrossing generation. After four successive backcrossing generations, the near-isogenic introgressions harboring Fhb7^The2 were developed in each of the Sumai 3, Frontana, and PI 277012 backgrounds. They are designated Sumai 3-Fhb7^The2, Frontana-Fhb7^The2, and PI 277012-Fhb7^The2, respectively. Their FHB severity was evaluated under controlled greenhouse conditions at 14- and 21-days post-inoculation (DPI), as well as in field trials at 21 days post-flowering (DPF) using corn spawn inoculation. Furthermore, we assessed Fusarium-damaged kernel (FDK) of the Fhb7^The2 introgressions and their recipient parents. Those analyses revealed that the Fhb7^The2 introgressions had enhanced resistance against FHB, exhibiting markedly reduced disease severity and lower FDK percentages than their respective recurrent parents. Frontana-Fhb7^The2 demonstrated a substantial reduction in FHB severity (16.89% vs. 47.84% at 21 DPI) and FDK (5.24% vs. 20.02%) relative to Frontana. Comparable trends were observed with Sumai 3-Fhb7^The2 in FHB severity (18.2% vs. 24.97% at 21 DPI) and FDK (2.36% vs. 11.17%), and with PI 277012-Fhb7^The2 in FHB severity (14.3% vs. 18.62% at 21 DPI) and FDK (4.77% vs. 7.23%). These improvements were statistically significant (p < 0.05) and consistent across different greenhouse and field conditions. Apparently, Fhb7^The2 shows an additive effect in these three major FHB resistance source lines. In addition, Fhb7^The2 shows a monogenic inheritance pattern and has no obvious detrimental agronomic effects from the alien translocation. All these results highlight Fhb7^The2 as a robust and effective FHB resistance source in wheat breeding.

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