Molecular mapping of QTLs for Fusarium head blight resistance in spring wheat. II. Resistance to fungal penetration and spread

Publication Type

Journal contribution

Authors

Buerstmayr, H., B. Steiner, L. Hartl, M. Griesser, N. Angerer. D. Lengauer, T. Miedaner, B. Schneider, and M. Lemmens

Year of publication

2003

Published in

Theor. Appl. Genet.

Band/Volume

107/

Page (from - to)

503-508

Fusarium head blight (FHB, scab) causes severe yield and quality losses, but the most serious concern is the mycotoxin contamination of cereal food and feed. The cultivation of resistant varieties may contribute to integrated control of this fungal disease. Breeding for FHB resistance by conventional selection is feasible but tedious and expensive. The aim of this work was to detect QTL for combined type I and type II resistance against FHB and estimate their effects in comparison to the QTL identified previously for type II resistance. A population of 364, F₁ derived doubled haploid (DH) lines from the cross 'CM-82036' (resistant) / 'Remus' (susceptible) was evaluated for components of FHB resistance during 2 years under field conditions. Plants were inoculated at anthesis with a conidial suspension of Fusarium graminearum or F. culmorum. The crop was kept wet for 20 hours after inoculation by mist-irrigation. Disease severity was assessed by visual scoring. Initial QTL analysis was performed on 239 randomly chosen DH lines and extended to 361 lines for putative QTL regions. Different marker types were applied, with an emphasis on PCR markers. Analysis of variance, as well as simple and composite interval mapping revealed that two genomic regions were significantly associated with FHB resistance. The two QTL on chromosomes 3B (Qfhs.ndsu-3BS) and 5A (Qfhs.ifa-5A) explained 29 and 20% of the phenotypic variance, respectively, for visual FHB severity. Qfhs.ndsu-3BS appeared to be associated mainly with resistance to fungal spread, and Qfhs.ifa-5A primarily with resistance to fungal penetration. Both QTL regions were tagged with flanking SSR markers. These results indicate that FHB resistance was under the control of two major QTL operating together with unknown numbers of minor genes. Marker assisted selection for these two major QTL appears feasible and should accelerate the development of resistant and locally adapted wheat cultivars.