Abstract
Breeding for Fusarium head blight (FHB) resistance in durum wheat is complicated by the quantitative trait expression and narrow genetic diversity of available resources. High-density mapping of the FHB resistance quantitative trait loci (QTL), evaluation of their co-localization with plant height and maturity QTL and the interaction among the identified QTL are the objectives of this study. Two doubled haploid (DH) populations, one developed from crosses between Triticum turgidum ssp. durum lines DT707 and DT696 and the other between T. turgidum ssp. durum cv. Strongfield and T. turgidum ssp. carthlicum cv. Blackbird were genotyped using the 90K Infinium iSelect chip and evaluated phenotypically at multiple field FHB nurseries over years. A moderate broad-sense heritability indicated a genotype-by-environment interaction for the expression of FHB resistance in both populations. Resistance QTL were identified for the DT707 × DT696 population on chromosomes 1B, 2B, 5A (two loci) and 7A and for the Strongfield × Blackbird population on chromosomes 1A, 2A, 2B, 3A, 6A, 6B and 7B with the QTL on chromosome 1A and those on chromosome 5A being more consistently expressed over environments. FHB resistance co-located with plant height and maturity QTL on chromosome 5A and with a maturity QTL on chromosome 7A for the DT707 × DT696 population. Resistance also co-located with plant height QTL on chromosomes 2A and 3A and with maturity QTL on chromosomes 1A and 7B for the Strongfield × Blackbird population. Additive × additive interactions were identified, for example between the two FHB resistance QTL on chromosome 5A for the DT707 × DT696 population and the FHB resistance QTL on chromosomes 1A and 7B for the Strongfield × Blackbird population. Application of the Single Nucleotide Polymorphic (SNP) markers associated with FHB resistance QTL identified in this study will accelerate combining genes from the two populations.
Highlights
Durum wheat (Triticum turgidum L. ssp. durum (Desf.) Husn.) is one of the major cereal food crops grown in the temperate regions of the world
By comparing the position of markers shared between the map generated in our study and the high-density tetraploid consensus map [17], we found the 5A2 quantitative trait loci (QTL) co-located with the Fusarium head blight (FHB) resistance QTL detected by Buerstmayr et al [21] from T. macha and that QTL detected by Zhang et al [27] from T. turgidum ssp. dicoccum
The detected loci varied in consistency of expression over environments, with the FHB QTL on chromosome 1A derived from cv
Summary
Durum wheat (Triticum turgidum L. ssp. durum (Desf.) Husn.) is one of the major cereal food crops grown in the temperate regions of the world. Fusarium head blight (FHB) causes severe reductions in grain yield and quality in the growing regions with moist and warm weather. Different types of FHB resistance have been identified in hexaploid wheat [2]. Resistance to initial infection or incidence is known as Type I resistance and resistance to spread or severity is known as Type II resistance, both of which have been extensively studied in hexaploid wheat [2,3]. Type I and II resistance are reported in the Canadian durum wheat line DT696 [4]. Using the available resistance in adapted sources such as line DT696 has the advantage of combining resistance in durum wheat cultivars with minimal detrimental effects of linkage drag, but such sources are rare within the breeding gene pool
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