Transfer of FHB resistance from Thinopyrum elongatum to bread wheat


Fedak, G., Wolfe, D., Chi, D., Ouellet, T., Cao, W., Xue, A. 2016. Transfer of FHB resistance from Thinopyrum elongatum to bread wheat. Proceedings of the 8th Canadian Workshop on Fusarium Head Blight, Ottawa, ON, November 20-22 2016. P 45.


Germplasm with good FHB resistance will normally contain a number of major resistance QTL plus a number of minor QTL all spread over the entire genome. It was thus unusual to find an aneuploid with a single chromosome (7E) introgressed from Thinopyrum elongatum (2x) to have high level of FHB resistance (9.6% infected florets following point inoculation compared to the parental cultivar at 57.5%). The ph1b mutant was used to induce recombination between chromosome 7E and a homoeologous wheat chromosome. The Ph mutant was crossed and backcrossed once to the three substitution lines 7E (7A), 7E (7B), 7E (7D) giving 556 BC1 seeds. The seeds were screened with marker PSR 574,
specific for Ph1b, and 43% of the BC1 progeny were found to be homozygous recessive for Ph1b. Those plants were inoculated with FHB spores and meiosis studied in them. Progeny from resistant plants
that showed complete chromosome pairing at meiosis were further analyzed. In excess of 500 BC1F1-F5 recombinants were screened with 7E-specific markers (Crop Sci 56:354-364, 2016; Genes Genom 34:67-75, 2012) and point inoculated with FHB spores, to isolate recombinants with FHB resistance and minimal introgression of 7E chromatin. The most promising recombinants were screened with markers from wheat chromosomes 7A, 7B and 7D to determine where the introgressions were located. Preliminary results indicate that the introgressions took place at marker WMC 150 on chromosome 7D, marker WMC10 on chromosome 7B and marker gwm554 on chromosome 7A. GISH analysis confirmed the locations of some of the introgressions.

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