Poster # 513

Harika Pothula¹, Evan Salsman¹, Jason Axtman¹, Suraj Basyal¹, Justin Hegstad¹, Yueqiang Leng², Zhao Jin¹, Shaobin Zhong³, Jason Fiedler⁴, Steven Xu⁵ , Elias Elias¹, and Xuehui Li¹
1. Department of Plant Sciences, North Dakota State University, Fargo, ND 58108-6050, USA
2. Department of Plant Pathology, North Dakota State University, Fargo, ND 58108-6050, USA
3. Cereal Disease Laboratory, USDA-ARS, St. Paul, MN 55108, USA
4. USDA-ARS, Edward T. Schafer Agricultural Research Center, Cereal Crops Improvement Research Unit, Fargo, North Dakota, USA
5. USDA-ARS, Crop Improvement and Genetics Research, Western Regional Research Center, Albany, California, USA
Corresponding Author: Xuehui Li, xuehui.li@ndsu.edu

Pothula, Harika

harika.pothula@ndsu.edu

Breeding for Fusarium head blight (FHB) resistance in durum wheat (Triticum turgidum L. subsp. durum) is particularly challenging due to the limited availability of resistant germplasm. Several durum wheat lines with moderate resistance, carrying different resistance genes, have been developed using resistant sources identified in tetraploid wheat relatives and hexaploid bread wheat. Given the complex genetic architecture of FHB resistance, recurrent selection provides an effective approach to improve resistance by integrating multiple resistance genes and increasing the frequency of favorable alleles. This strategy also enhances the likelihood of developing FHB-resistant inbred lines from the improved populations. A base population was developed by crossing ten moderately FHB-resistant lines with five elite durum wheat cultivars. Five cycles of phenotypic selection for FHB severity were conducted from 2019 to 2024, one cycle per year. The mean FHB severity decreased from 82.5% in Cycle 0 to 59.3% in Cycle 5. A genomic prediction model was developed using 318 breeding lines from the NDSU durum program and 438 S_0:1 lines from recurrent selection Cycle 3–5 populations. Prediction accuracies were 0.51 for FHB severity, 0.53 for plant height, and 0.79 for days to flowering. Two cycles of genomic selection (GS), initiated with the top 15 S_0:1 lines from the Cycle 5 population, were conducted from September 2024 to April 2025. Field evaluations in 2025 showed progressive improvement in FHB severity across GS cycles at both locations. The top 24 lines selected from GS-Cycle 0–2 were genotyped using the KASP marker for Fhb1, revealing that over 65% of lines carried the resistant allele. Several of these top lines also exhibited significantly lower FHB severity and deoxynivalenol (DON) content compared with the check cultivar ND Riveland at both Fargo and Prosper, ND. These results demonstrate the effectiveness of recurrent phenotypic selection and genomic selection in enhancing FHB resistance in durum wheat, providing a strong foundation for developing resistant cultivars adapted to the Northern Great Plains.

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