Poster # 503

Ahmed Charif ^1,2, Fang Wang ^1,2, Tatiana Danilova ², Katherine Frels ¹, Raja Sekhar Nandety ³, Jason Fiedler ³, Deanna Funnell-Harris ², Jeffrey Boehm Jr. ^2,1, and Xiwen Cai ^2,1
1. Department of Agronomy and Horticulture, University of Nebraska, Lincoln, NE 68583, USA
2. USDA-ARS, Wheat, Sorghum & Forage Research Unit, Lincoln, NE 68583, USA
3. USDA-ARS, Cereal Crops Research Unit, Edward T. Schafer Agricultural Research Center, Fargo, ND 58102, USA
Corresponding Author: PH: 402-326-4055; Email: xiwen.cai@usda.gov

Ahmed Charif

Hexaploid wheat (Triticum aestivum L.)-derived Fusarium head blight (FHB) resistance genes do not express normally in the tetraploid durum wheat (T. turgidum L. ssp. durum) backgrounds probably because of epistatic effects. This study aimed to map hexaploid wheat-derived FHB resistance QTL in the recombinant inbred lines (RILs) derived from the cross of durum cultivar ‘Divide’ by hexaploid wheat accession PI 277012. Divide exhibits moderate resistance to FHB and PI 277012 exhibits high levels of FHB resistance comparable to Sumai 3. In previous studies, two major FHB resistance QTL were identified in PI 277012 and mapped to the short and long arms of chromosome 5A. The RIL population (n=203) was phenotyped for FHB resistance under controlled greenhouse conditions and genotyped using Illumina’s wheat 90K SNP arrays. No D-genome chromosomes were detected in the RILs using D genome-specific markers. Substantial phenotypic variation for FHB severity was observed in the RIL population. A linkage map including all 14 A- and B-genome chromosomes was construct using the RIL population. Seven FHB resistance QTL with 3.7% to 10.6% phenotypic variation were identified in the RIL population. Three of them mapped to chromosome 5A, two to 4A, one to 2B, and one to 5B. Out of the seven resistance QTL, four were contributed by PI 277012 and three by Divide. In addition, epistasis was investigated within this RIL population. A total of 25 minor epistatic interactions between loci of the A and B genomes with a LOD score greater than six were detected. The additive-by-additive effects of epistatic QTL were comparatively higher than the additive effect at any corresponding loci. A second season of screening for FHB resistance is in progress to validate these results. Integrative QTL analysis will also be performed using this RIL population and others with shared parents to further examine epistasis of FHB resistance QTL in the tetraploid wheat backgrounds. The exploration of epistatic effects among FHB resistance QTL will enhance our understanding of the interactions between FHB resistance genes, and identify the combinations that enhance resistance.