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Development of molecular markers for crown rot resistance in wheat: mapping of QTLs for seedling resistance in a '2-49' x 'Janz' population

Collard, B.C.Y., Grams, R.A., Bovill, W.D., Percy, C.D., Jolley, R., Lehmensiek, A., Wildermuth, G., Sutherland, M.W.
Plant breeding 2005 v.124 no.6 pp. 532-537
Triticum aestivum, wheat, disease resistance, Fusarium pseudograminearum, plant pathogenic fungi, crown rot, quantitative trait loci, chromosome mapping, genetic markers, inheritance (genetics), phenotypic variation, alleles, seedlings
Crown rot, caused by Fusarium pseudograminearum, is an important disease of wheat in Australia and elsewhere. In order to identify molecular markers associated with partial seedling resistance to this disease, bulked segregant analysis and quantitative trait loci (QTL) mapping approaches were undertaken using a population of 145 doubled haploid lines constructed from '2-49' (partially resistant) x 'Janz' (susceptible) parents. Phenotypic data indicated that the trait is quantitatively inherited. The largest QTLs were located on chromosomes 1D and 1A, and explained 21% and 9% of the phenotypic variance, respectively. Using the best markers associated with five QTLs identified by composite interval mapping, the combined effect of the QTLs explained 40.6% of the phenotypic variance. All resistance alleles were inherited from '2-49' with the exception of a QTL on 2B, which was inherited from 'Janz'. A minor QTL on 4B was loosely linked (19.8 cM) to the Rht1 locus in repulsion. None of the QTLs identified in this study were located in the same region as resistance QTLs identified in other populations segregating for Fusarium head blight, caused by Fusarium graminearum.