Genome-wide Association Mapping of Fusarium Head Blight Resistance and Agromorphological Traits in Barley Landraces from Ethiopia and Eritrea
Tuesday, 2015/07/14 | 07:57:13
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Bullo Erena Mamo and Brian J. Steffenson CROP SCIENCE June 15, 2015; Vol. 55 No. 4, p. 1494-1512 AbstractFusarium head blight (FHB), caused primarily by Fusarium graminearum, is an important disease of barley (Hordeum vulgare L.), and other cereals. In barley, the genetic basis of FHB resistance has been intensively studied through linkage mapping that identified several quantitative trait loci (QTL). However, our understanding and application of these QTL in breeding is still limited due to the complex nature and low-to-moderate heritability of FHB resistance. Previous studies used either breeding lines, unimproved varieties, or germplasm selections. Here, we used association mapping in barley landraces to identify QTL associated with FHB severity, deoxynivalenol (DON) concentration and correlated agromorphological traits. Diverse barley landraces (n = 298) from Ethiopia and Eritrea were evaluated for the traits under field conditions for 2 yr (2011–2012) in Crookston, MN, and genotyped with 7842 single nucleotide polymorphism (SNP) markers. Association mapping analysis using a mixed model corrected for pairwise relatedness between individuals identified one common resistance QTL on barley chromosome 2HL significantly associated with both FHB severity and DON concentration and another one on 4HL associated with DON concentration. The QTL identified on 2HL is associated with the row-type locus Vrs1. Both of these QTL were not significantly associated with heading date or plant height unlike other QTL reported in previous studies. Thus, the resistant accessions carrying these QTL may be used in breeding programs without the confounding effects from these agromorphological traits. Importantly, these QTL could be new alleles preserved in this unique germplasm, and the linked SNP markers found may be useful in marker-assisted introgression of resistance.
See: https://dl.sciencesocieties.org/publications/cs/abstracts/55/4/1494
Figure 2. Genome-wide association scan for marker associations with Fusarium head blight (FHB) severity, deoxynivalenol (DON) concentration, and kernel density (KD) in the Ethiopian and Eritrean Barley Collection (EEBC) evaluated at Crookston, MN in 2011 and 2012. Scans are shown for (A) FHB severity for the whole set of landrace germplasm combined over 2 yr (EEBC-C); (B) DON concentration for the whole set of landrace germplasm combined over 2 yr (EEBC-C); (C) DON concentration for the individual year of 2012 (EEBC-12); (D) combined DON concentration in the six-rowed germplasm set (EEBC-6-rowed-C) only; (E) DON concentration in the six-rowed germplasm set in 2012 (EEBC-6-rowed-12) only; (F) combined DON concentration in the two-rowed germplasm set (EEBC-2-rowed-C) only; (G) DON concentration in the two-rowed germplasm set in 2011 (EEBC-2-rowed-11) only; and (H) kernel density for the whole set of landrace germplasm combined over 2 yr (KD-EEBC-C). Vertical axis represents log10(P-values) of the marker–trait associations after correction for multiple testing, and the horizontal axis represents the relative chromosomal position of the single nucleotide polymorphism (SNP) markers across the genome. The black horizontal dotted lines show the P-value corresponding to a false discovery rate (FDR) of 0.05. The SNP markers with peaks above this threshold level were considered as significantly associated. The most significant marker for each trait or analysis panel is marked with arrows. The full names of two of the most significant markers indicated in (G) on chromosome 2HL are SCRI_RS_130072 and SCRI_RS_139737. |
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