ARS | Publication request: Fusarium head blight resistance in durum wheat

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: November 13, 2011
Publication Date: December 4, 2011
Citation: Cai, X., Elias, E., Xu, S.S., Kianian, S., Zhong, S., Chao, S. 2011. Fusarium head blight resistance in durum wheat – progress and challenge. Meeting Abstract. pg.12.

Technical Abstract: Several sources of FHB resistance have been identified in tetraploid wheat, including durum (Triticum turgidum ssp. durum, genome AABB), emmer (T. turgidum ssp. dicoccum, genome AABB), wild emmer (T. turgidum ssp. dicoccoides, genome AABB), Persian wheat (T. turgidum ssp. carthlicum, genome AABB) and timopheevii wheat (T. timopheevii, genome AAGG). None of these resistance sources is comparable to ‘Sumai 3’, a major source of resistance found in hexaploid wheat (T. aestivum L., genome AABBDD). We have identified and mapped several novel FHB resistance QTL from the tetraploid sources, including Qfhs.ndsu-3AS from wild emmer, Qfhs.ndsu-5BL from durum, and Qfhb.rwg-5A.1 and Qfhb.rwg-5A.2 possibly from timopheevii. Molecular markers have been developed to tag these resistance QTL and used to assist selection of the QTL in the germplasm/cultivar development. Significant efforts have been made to introgress FHB resistance from the tetraploid and hexaploid sources into adapted durum backgrounds. Durum cultivars with improved FHB resistance, such as Divide, have been released and widely grown in ND. In addition, a large number of durum germplasm lines with various levels of resistance have been developed. However, the durum lines with resistance QTL from the tetraploid and hexaploid sources have always exhibited lower levels of resistance than the original sources or no resistance at all especially under field conditions. This has been a big puzzle and challenge for durum researchers to develop durum cultivars and germplasm with high levels of resistance to FHB. Recently, we have identified FHB resistance QTL on chromosome 5A and 5B of a moderately resistant synthetic hexaploid wheat line (genome AABBDD) derived from the cross of the susceptible durum cultivar ‘Scoop 1’ (genome AABB) and Aegilops tauschii (genome DD). These results suggest that D genome might have the capacity to boost expression of FHB resistance genes in A and B genomes. Further studies are being performed on the role of the D-genome chromosomes in the expression of FHB resistance QTL derived from A and B genomes. Additionally, a possible susceptibility or suppressor of resistance locus on durum chromosome 2A has been identified. Efforts are underway to remove or mutate this locus to further characterize its effect and increase the resistance in adapted cultivars.