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Improving resistance to Fusarium head blight in winter wheat by genomic selection

Thomas Miedaner: University of Hohenheim (720)

<div>Fusarium head blight (FHB), caused by <em>Fusarium graminearum</em>, <em>F. culmorum</em> and other species, is a devastating disease in many wheat growing areas resulting in yield and quality losses and contamination of mycotoxins harmful for man and livestock. Although fungicides exist, breeding resistant cultivars is the most effective and environmentally friendly measure to control FHB. Resistance is inherited quantitatively by many genes with small effects making marker-assisted selection inefficient. The availability of phenotypes and a high-density marker array in wheat allows to use the information from the whole genome to predict FHB resistance (=genomic selection, GS). We analyzed two training populations with a total of 1,180 winter wheat lines for FHB resistance, heading date, and plant height at four locations and genotyped them by an 15k Illumina SNP assay. Mean FHB symptoms varied from 5 to 60% among the lines. Prediction accuracies for FHB resistance ranged from 0.36 to 0.74 depending on the genetic relatedness of the progenies. From a test population of 2,500 progenies the best 10% for FHB resistance have been selected by their genomic composition. We explore now the realized selection gain for this GS approach by field phenotyping the genomically selected progenies in 2018. In conclusion, GS would make FHB resistance more efficient, because larger populations can be screened in a shorter time period with less efforts for field plots and locations.</div>