High-density genetic mapping of Fusarium head blight resistance and agronomic traits in spring wheat

Abstract

Fusarium head blight (FHB) has rapidly become a major challenge to successful wheat production and competitive end-use quality in western Canada. Continuous effort is required to develop germplasm with improved FHB resistance and understand how to incorporate the material into crossing schemes for marker-assisted selection and genomic selection. The aim of this study was to map quantitative trait loci (QTL) responsible for the expression of FHB resistance in two adapted cultivars and to evaluate their co-localization with plant height, days to maturity, days to heading, and awnedness. A large doubled haploid population of 775 lines developed from cultivars Carberry and AC Cadillac was assessed for FHB incidence and severity in nurseries near Portage la Prairie, Brandon, and Morden in different years, and for plant height, awnedness, days to heading, and days to maturity near Swift Current. An initial linkage map using a subset of 261 lines was constructed using 634 polymorphic DArT and SSR markers. QTL analysis revealed five resistance QTL on chromosomes 2A, 3B (two loci), 4B, and 5A. A second genetic map with increased marker density was constructed using the Infinium iSelect 90k SNP wheat array in addition to the previous DArT and SSR markers, which revealed two additional QTL on 6A and 6D. The complete population was genotyped, and a total of 6,806 Infinium iSelect 90k SNP polymorphic markers were used to identify 17 putative resistance QTL on 14 different chromosomes. As with the smaller population size and fewer markers, large-effect QTL were detected on 3B, 4B, and 5A that were consistently expressed across environments. FHB resistance QTL were co-localized with plant height QTL on chromosomes 4B, 6D, and 7D; days to heading on 2B, 3A, 4A, 4B, and 5A; and maturity on 3A, 4B, and 7D. A major QTL for awnedness was identified as being associated with FHB resistance on chromosome 5A. Nine small-effect QTL were not associated with any of the agronomic traits, whereas 13 QTL that were associated with agronomic traits did not co-localize with any of the FHB traits. There is an opportunity to select for improved FHB resistance within adapted cultivars by using markers associated with complementary QTL.

Genetic mapping of deoxynivalenol and fusarium damaged kernel resistance in an adapted durum wheat population

“…At both Morden and Indian Head, the experiments were conducted as an augmented randomized block design with 19 entries per incomplete block including six FHB standard checks used in FHB evaluation of wheat breeding lines for the wheat variety registration (from resistant to susceptible) and two parents. Sixty seeds were planted per line on 1 m row plots using a six-row cassette Wintersteiger planter as recently described in detail by Berraies et al [ 75 ]. The FHB standard checks AAC Tenacious, 5602 h, FHB37, CDC Teal, AC Morse, and AC Cora were replicated nine times in the experiment.…”

“…The protocol for the F. graminearum corn kernel inoculum preparation was adopted from Gilbert and Woods [ 76 ]. The F. graminearum isolates used, the method of the inoculum application and the details on data collection were described previously by Berraies et al [ 75 ]. Briefly, the FHB corn inoculum was applied when the plants reached 4–6 leaf stage and repeated a week after the first application, which was followed by third application after 7 days.…”

“…The QTL analysis was performed using the MapQTL6® [ 79 ] software for the DON and FDK as described in a previous study [ 75 ]. In short, the analysis was first conducted using Kruskal–Wallis (KW) test option in the MapQTL to determine the association between marker and FHB traits.…”

“…QTL confidence intervals were estimated by 1.3-LOD support interval with 99% confidence interval probability coverage. The thresholds of logarithm of odds (LOD) scores for significant QTL ( P < 0.05) were determined by performing 1000 permutations on the genome-wide level [ 75 ]. Significant QTL and regions were visualized using the software MapChart 2.1.…”

Update on the Basic Understanding of Fusarium graminearum Virulence Factors in Common Wheat Research

“…Previous studies have speculated on the negative correlation between FHB severity, plant height, and anther exclusion. It has been suggested that tall genotypes without anthers could have some level of resistance against FHB [ 87 , 88 , 89 , 90 , 91 ]. Recent studies have uncovered the underlying mechanism of glutathione S-transferase (GST) encoded by Fhb7.…”