High density genetic mapping of Fusarium head blight resistance QTL in tetraploid wheat
Sari, E., Berraies, S., Knox, R.E., Singh, A.K., Ruan, Y., Cuthbert, R.D., Pozniak, C.J., Henriquez, M.A., Kumar, S., Burt, A.J., N'Diaye, A., Konkin, D.J., Cabral, A.L., Campbell, H.L., Wiebe, K., Condie, J., Lokuruge, P., Meyer, B., Fedak, G., Clarke, F.R., Clarke, J.M., Somers, D.J., Fobert, P.R. (2018). High density genetic mapping of Fusarium head blight resistance QTL in tetraploid wheat. PLoS ONE, [online] 13(10), http://dx.doi.org/10.1371/journal.pone.0204362
Plain language summary
Durum wheat is susceptible to Fusarium head blight which causes yield loss, and infected grain reduces processing quality and poses a health risk. Resistance is controlled by many small effect genes making breeding difficult. DNA markers to resistance genes can help breeders assemble the genes. A number of resistance genes were identified from conventional durum cultivars and a close relative to conventional durum by using modern genetic technologies. The markers will allow genes currently dispersed among durum cultivars to be stacked into a single cultivar to improve overall resistance to Fusarium head blight. Varieties with better Fusarium head blight resistance will improve the stability of farmers durum production, improve market value of their grain and reduce the risk to the health of conumers.
Breeding for Fusarium head blight (FHB) resistance in durum wheat is complicated by the quantitative trait expression and narrow genetic diversity of available resources. High-density mapping of the FHB resistance quantitative trait loci (QTL), evaluation of their co-localization with plant height and maturity QTL and the interaction among the identified QTL are the objectives of this study. Two doubled haploid (DH) populations, one developed from crosses between Triticum turgidum ssp. durum lines DT707 and DT696 and the other between T. turgidum ssp. durum cv. Strongfield and T. turgidum ssp. carthlicum cv. Blackbird were genotyped using the 90K Infinium iSelect chip and evaluated phenotypically at multiple field FHB nurseries over years. A moderate broad-sense heritability indicated a genotype-by-environment interaction for the expression of FHB resistance in both populations. Resistance QTL were identified for the DT707 × DT696 population on chromosomes 1B, 2B, 5A (two loci) and 7A and for the Strongfield × Blackbird population on chromosomes 1A, 2A, 2B, 3A, 6A, 6B and 7B with the QTL on chromosome 1A and those on chromosome 5A being more consistently expressed over environments. FHB resistance co-located with plant height and maturity QTL on chromosome 5A and with a maturity QTL on chromosome 7A for the DT707 × DT696 population. Resistance also co-located with plant height QTL on chromosomes 2A and 3A and with maturity QTL on chromosomes 1A and 7B for the Strongfield × Blackbird population. Additive × additive interactions were identified, for example between the two FHB resistance QTL on chromosome 5A for the DT707 × DT696 population and the FHB resistance QTL on chromosomes 1A and 7B for the Strongfield × Blackbird population. Application of the Single Nucleotide Polymorphic (SNP) markers associated with FHB resistance QTL identified in this study will accelerate combining genes from the two populations.