Single Nucleotide Polymorphim Markers for Fusarium Head Blight Resistance in Wheat.

Fusarium head blight (FHB) is a devastating disease in humid and semi-humid wheat growing regions worldwide. The quantitative trait locus (QTL) on 3BS (Fhb1) of Sumai 3 and Ning 7840 has been identified to have the largest effect on FHB resistance. Simple sequence repeat (SSR) markers flanking the Fhb1 locus have been identified and widely used in marker-assisted selection (MAS) of Fhb1. However, these SSR markers flank a relatively large chromosome region of the QTL and more closely linked markers to the QTL may improve selection efficiency. The rich sources of wheat expressed sequence tags (ESTs) and abundance of single nucleotide polymorphism (SNP) markers make SNP an ideal marker for fine mapping and MAS. We developed SNP markers based on wheat ESTs that mapped to Fhb1 QTL region. A total of 15 polymorphisms (SNPs and indels) were identified between Ning 7840 and Clark (FHB-susceptible) based on sequence analysis of three different ESTs. The SNPs were analyzed in 125 recombinant inbred lines (RILs) derived from cross Ning 7840 / Clark using single-base-extension method. One SNP marker per EST was developed and mapped between Xgwm533 and Xgwm493. SNPs Xsnp-21 and Xsnp–20-1a showed higher coefficients of determination (R²) than that of Xgwm533 in population Ning 7840 / Clark based on both field and greenhouse FHB data and can be used for high-throughput screening of the Fhb1 in breeding programs.