LAUSR

Fusarium head blight (FHB) is a destructive wheat disease worldwide and significantly affects grain yield and quality in wheat. To understand the genetic basis underlying type II FHB resistance in two elite wheat cultivars Yangmai 4 (YM4) and Yangmai 5 (YM5), quantitative trait loci (QTL) mapping was conducted in two recombinant inbred lines (RIL) populations derived from the crosses of YM4 and YM5 with susceptible cultivar Yanzhan 1 (YZ1), respectively. Survey with markers linked to Fhb1, Fhb2, Fhb4, and Fhb5 in landrace Wangshuibai indicated the non-existence of these known FHB resistance genes/QTL in YM4, YM5, and YZ1. One overlapped resistance QTL was identified in both RIL populations, namely QFhb.Y4.2D/QFhb.Y5.2D, with a large effect on FHB resistance. One novel resistance QTL QFhb.Y4.5A mapped on chromosome 5A was detected only in YM4/YZ1 population. The resistance alleles of both QFhb.Y4.2D/QFhb.Y5.2D and QFhb.Y4.5A did not increase the plant height and did not significantly affect the heading date and flowering date. Kompetitive Allele-Specific PCR markers for QFhb.Y4.2D/QFhb.Y5.2D and QFhb.Y4.5A had been developed to verify in an additional set of 244 geographically diverse cultivars/lines. Pyramiding of the two resistance alleles decreased the percentage of symptomatic spikelets by 51.77% relative to the cultivars/lines without these two resistance alleles. QFhb.Y4.2D/QFhb.Y5.2D and QFhb.Y4.5A were shown to be useful alternatives in FHB resistance breeding programs. The results will facilitate the marker-assisted selection for introgression of the favorable alleles for improving FHB resistance in breeding programs.