Stacking Fhb1, photoperiod/anthesis, and plant height genes in elite winter wheat lines using genomic tools and evaluate yield performance of lines in different groups

Objectives:

• To use a previously developed bi-parental wheat population, which segregates for Fusarium head blight (FHB) and deoxynivalenol (DON), to estimate the relationship between fhb1, plant height genes (Rht8 and Rht-B1), photoperiod/anthesis gene (Ppd-D1), and agronomic performance.
• To investigate if there are yield penalties associated with fhb1 and plant height (tall vs. short).
• To investigate if there are yield penalties associated with fhb1 and photoperiod/anthesis (sensitive/late vs. insensitive/early lines).
• To validate selected lines with/without fhb1 (3BS) for FHB, Fusarium damaged kernels (FDK) and DON after inoculation with Fusarium

• To develop improved germplasm or cultivars.

Impacts:

• Growers will have an opportunity to grow high-yielding eastern Canadian soft red winter wheat with increased resistance to FHB and overall good yield and quality.
• Better marketing opportunities for wheat produced in Ontario (Canadian Eastern Soft Red class is important for domestic processing and export).
• Reduced losses for farmers and grain handlers due to lower DON levels and a more stable supply of safe low-DON wheat for robust domestic and export processing markets.
• More stable winter wheat yield and quality due to a reduction in downgrading (lower prices for farmers).
• Potential for less fungicide use due to new germplasm/cultivars with increased resistance to FHB could mean fewer field passes will be needed to apply fungicides (which also has a carbon benefit from reduced fuel and fungicide production).

Project Overview:

Wheat is a major food crop. Fusarium head blight (FHB) is an important wheat disease. Winter wheat has higher yield potential than spring wheat. The economic loss from FHB is high. Currently, we have moderately FHB-resistant wheat in Ontario, but a higher level of resistance is needed. FHB-related traits (visual symptoms, Fusarium damaged kernels (FDK) and deoxynivalenol (DON)) are influenced by multiple genes or quantitative trait loci (QTL) with medium effect. Multiple types of FHB resistance exist and have been categorized into five groups: type I (resistance to initial infection in the spike), type II (resistance to pathogen spread in the spike after infection), type III (resistance to kernel infection), type IV (tolerance to yield reduction), and type V (tolerance to DON accumulation). Breeding high yielding winter wheat with short, strong straw and good FHB resistance remains a challenge for breeders. Rht8c/Ppd1 linkage group (2D) is used in breeding wheat to improve the adaptability to areas with hot and dry conditions. With increasing temperature during wheat development, wheat with this linkage group is important for growers.

A double haploid (DH) winter wheat population ‘25R51’ x ‘Triumph’ (102 lines) was used in this study. The population was genotyped using an Illumina 90K Bead chip platform based on single nucleotide polymorphism (SNP) technology and further screened with selected KASP markers. Fhb1 (3BS) is a major gene/QTL from ‘Sumai 3’ (parent of ‘25R51’). The population was segregated for fhb1, plant height genes Rht8 and Rht-B1, and photoperiod/anthesis gene Ppd1 (2D QTL). An effective use of molecular markers is for marker assisted selection (MAS). Our goal was to select lines according to: 1) 3BS (fhb1) as resistant vs. susceptible, 2) photoperiod/anthesis gene (sensitive/late and insensitive/early) and 3) plant height gene (short and tall). We evaluated performance of selected lines, in each group, for agronomic and quality traits. MAS was validated for fhb1 in an inoculated FHB nursery where lines were evaluated for FHB symptoms, FDK, and DON. The final goal was to develop winter wheat germplasm/cultivars.

Results:

Environment influenced heading date and plant height across the population. The 2024 and 2025 growing seasons were similar in terms of heading date (early) and plant height (taller) compared to the 2023 growing season, when lines headed later and were shorter. However, screening with KASP markers identified early heading vs later heading lines and shorter vs taller lines and it is recommended to apply screening early in population development to save time compared to field evaluation. Higher prediction of plant height was obtained using KASP marker Rht-B1 than marker Rht8. FHB resistance was linked to plant height/days to anthesis QTL on 2D (Ppd-D1), but the plant height QTL on 4B (Rht-B1) was independent from FHB resistance. This is considered a significant result as breeders struggle to dissociate FHB and plant height traits. Fhb1 was found to have no significant detrimental influence on yield, which is important and positive information for breeders. Breeding lines Ca26-72, Ca26-95, and Ca26-100 were identified as good germplasm as they have favorable alleles for Rht8, Rht-B1, fhb1, and Ppd-D1 and they will be used as parents in crosses. These lines also showed resistance to other diseases: powdery mildew, stripe rust, leaf rust, and Septoria. In addition, lines Ca26-14, Ca26-46, and Ca26-74 had higher yield than parent 25R51. The transgressive segregants that outperformed parental lines for yield and FHB resistance will be additionally evaluated for yield. Due to quantitative nature of FHB resistance, incorporation of the fhb1 gene needs to be combined with additional FHB resistance genes.

External Funding Partners:

This work was supported by Mitacs through the Mitacs Accelerate Program.

Project Related Publications:

Neupane, A., Tamburic-llincic, L., Brûlé-Babel, A., and McCartney, C. 2025. Genetic improvement of FHB and DON resistance by combining the Fhb1 gene with additional resistance QTL in winter wheat population. The Plant Genome. 18(3): e70084.