ARS | Publication request: Identification and molecular mapping of two QTLs with major effects for resistance to Fusarium head blight in wheat

Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 28, 2011
Publication Date: November 1, 2011
Citation: Chu, C., Niu, Z., Zhong, S., Chao, S., Friesen, T.L., Halley, S., Elias, E.M., Dong, Y., Faris, J.D., Xu, S.S. 2011. Identification and molecular mapping of two QTLs with major effects for resistance to Fusarium head blight in wheat. Theoretical and Applied Genetics. 123(7):1107-1119.

Interpretive Summary: Since the mid 1990s, bread wheat and durum wheat production in North America and many other wheat-growing regions in the world have been seriously threatened by Fusarium head blight (FHB). The epidemics of this disease have caused serious economic losses in Canada and the United States over the past 16 years. Because the utilization of FHB-resistant cultivars is an effective approach for protecting wheat against FHB, new sources of FHB resistance have been in high demand by wheat breeders. From a large-scale evaluation of wheat germplasm for resistance to FHB, we identified one wheat line (PI 277012) that consistently showed a high level of resistance in both greenhouse and field experiments. To characterize the FHB resistance in this line, we developed a population consisting of 130 pure lines derived from the cross between PI 277012 and the hard red spring wheat cultivar ‘Grandin’. The population was then used to develop a genetic map using 340 molecular markers and it was also evaluated for resistance to FHB in three greenhouse seasons and five field environments. Based on the genetic map and FHB evaluation data, we identified two major FHB resistance genes on short arm and long arm of chromosome 5A. The gene on the long arm of chromosome 5A has not previously been reported, thus indicating the novelty of FHB resistance in PI 277012. Genetic analysis showed that plant maturity was not associated with FHB resistance and the effects of plant height on FHB resistance were minor. Therefore, PI 277012 is an excellent source for improving FHB resistance in wheat. The molecular markers identified in this research are being used for marker-assisted deployment of the two genes into adapted durum and hard red spring wheat cultivars.

Technical Abstract: Fusarium head blight (FHB) is a devastating disease of wheat worldwide. Novel sources of resistance are critical for improving FHB resistance levels in wheat. From a large-scale evaluation of germplasm for reactions to FHB, we identified one wheat accession (PI 277012) that consistently showed a high level of resistance in both greenhouse and field experiments. To characterize the FHB resistance in this accession, we developed a doubled haploid (DH) mapping population consisting of 130 lines from the cross between PI 277012 and the hard red spring wheat cultivar ‘Grandin’. The DH population was then evaluated for reactions to FHB in three greenhouse seasons and five field environments. Based on a linkage map that consisted of 340 SSR markers spanning 2,703 cM of genetic distance, two major FHB resistance QTLs were identified on chromosome arms 5AS and 5AL, with each explaining up to 20% and 32% of the variation in FHB severity, respectively. The two QTLs also showed major effects on reducing the percentage of Fusarium damaged kernels (FDK) and deoxynivalenol (DON) accumulation in seeds. FHB resistance has not previously been reported to be associated with this particular genomic region of chromosome arm 5AL, thus indicating the novelty of FHB resistance in PI 277012. Plant maturity was not associated with FHB resistance and the effects of plant height on FHB resistance were minor. Therefore, these results suggest that PI 277012 is an excellent source for improving FHB resistance in wheat. The markers identified in this research are being used for marker-assisted introgression of the QTLs into adapted durum and hard red spring wheat cultivars.