|Mittal, Shipra -|
|Hill, Nicholas -|
Submitted to: Plant Breeding
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 18, 2011
Publication Date: January 1, 2012
Citation: Dahleen, L.S., Morgan, W.C., Mittal, S., Bregitzer, P.P., Brown, R.H., Hill, N.S. 2012. Quantitative trait loci (QTL) for Fusarium ELISA compared to QTL for Fusarium head blight resistance and deoxynivalenol content in barley. Plant Breeding. 131:237-243. Interpretive Summary: Fusarium head blight (FHB, scab) and the resulting mycotoxin deoxynivalenol (DON) contamination reduce barley yield and quality. Very few barley varieties show resistance to this disease. We located regions of the barley chromosomes associated with resistance to FHB, DON, and a biochemical assay (ELISA) specific to fungi that cause the disease, in the resistant variety Zhedar 2. We found six regions associated with FHB resistance, including one that also was associated with low DON and another associated with the ELISA measurements. Three of the FHB regions appear to be unique to Zhedar 2. Many of these regions also were associated with plant height and days to flowering, showing that plant structure influences disease levels. Plants with closed flowers had lower disease levels in two environments, but the effects of closed versus open flowering were not consistent in other environments, probably because FHB was present throughout seed development.
Technical Abstract: : <p>Fusarium head blight (FHB) and the deoxynivalenol (DON) mycotoxin produced by the causal agent Fusarium graminearum have reduced barley yield and quality throughout the world. This study was conducted to locate quantitative trait loci (QTL) for FHB, DON, heading date, height, and spike density, and compare them to locations of QTL detected by an enzyme-linked immunosorbent assay (ELISA) using an antibody specific to Fusarium species; to compare different QTL analyses methods; and to determine whether cleistogamous flowering is associated with FHB resistance in field environments. Doubled haploid lines derived from the cross Zhedar 2/ND9712//Foster were tested in ten environments and used to develop a linkage map with 260 marker positions. QTL analysis located 17 significant chromosome regions for the six traits using composite interval mapping (CIM) and another 7 regions using the generalized linear model for multiple interval mapping (MIM-GLZ), confirming many of the QTL previously located in a subset of this population. The effect of cleistogamy on resistance was unclear and environment-specific. Of the two QTL located for ELISA, only one corresponded with a QTL for FHB and none with DON QTL. This was not surprising considering the moderate correlations between ELISA results, DON, and FHB, and the low heritability for FHB and DON.