Fine mapping of a major wheat QTL for Fusarium head, blight resistance

摘要

A major QTL, Qfhs.ndsu-SBS, for resistance to Fusarium head blight (FFffi) in wheat has been identified and verified by several research groups. The objectives of this study were to develop STS (sequence-tagged site) markers from wheat ESTs homologousto the corresponding genomic sequences of rice, and to construct a high resolution map of the Qfhs.ndsu-SBS region. The sequences of PI-derived artificial chromosome (PAC)/bacterial artificial chromosome (BAC) clones covering the sub-distal portion of rice chromosome 1S were used as queries for BLASTN search to identify wheat ESTs most likely near Qfhs.ndsu-SBS. Sixty-eight out of 79 STS primer pairs designed from wheat ESTs amplified PCR products from the genomic DNA of wheat cultivar 'Chinese Spring'. Twenty-eight STS markers were localized on chromosome 3BS by aneuploid analysis. Six out of the nine STS markers mapped in the Sumai 3/Stoa population had higher i?" and LOD values for this QTL than the most significant marker reported previously. Sixteen hundred F2 plants derived from a single F7 plant heterozygous for the Qfhs.ndsu-SBS region were screened for recombinants with two SSR markers, gwm533 and gwm493, and 192 recombinants were identified. Five STS markers and two additional SSR markers were used to genotype the 192 recombinants, and a fine genetic map was constructed. Homozygous recombinants were identified in the F3 generation, and F4 seeds will be used for phenotypic analysis of FHB reaction to precisely locate Qfhs.ndsu-SBS to a narrow marker interval.