Eco-Tilling for Fusarium Head Blight Resistance in Hexaploid Wheat

Fusarium Head Blight (FHB), which is most commonly caused by the fungus Fusarium graminearum, is becoming more of a concern on the Canadian Prairies. Besides reducing yields, FHB damage reduces end-use quality, largely due to the production of mycotoxins by F. graminearum.  Our objectives were to identify naturally-occurring inactive variants of genes that contribute to increased susceptibility to FHB, to develop markers for these variants, and to combine A-, B- and D-subgenome derived copies of these genes by traditional breeding methods.  Genes expected to increase susceptibility were identified by various methods, such as expression studies followed virus-induced gene silencing (VIGS), or through reviews of the literature. A collection of several hundred lines including landraces and varieties from throughout the world were screened for inactive variants of genes of interest using a “tilling by sequencing” approach.  After variants were traced to single lines, sequence information was used to develop markers capable of distinguishing variant and wild-type alleles. These markers were used to efficiently produce plants containing combinations of one, two or three inactive homoeologous genes.