The genetic architecture of seedling resistance to Septoria tritici blotch in the winter wheat doubled-haploid population Solitär × Mazurka

• Published in: Molecular breeding Vol. 29; no. 3; pp. 813 - 830
• Main Authors: Kelm, Christiane, Ghaffary, S. Mahmod Tabib, Bruelheide, Helge, Röder, Marion S., Miersch, Sebastian, Eberhard Weber, W., Kema, Gert H. J., Saal, Bernhard
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 2012; Springer Nature B.V
• Subjects: Biomedical and Life Sciences; Biotechnology; bread wheat; chromosomal location; Chromosomes; Cultivars; d-genome; Disease control; Epistasis; Foliar diseases; Gene mapping; Genetic effects; Heredity; hexaploid wheat; Imperfect state; Life Sciences; linkage maps; Mapping; microsatellite markers; Molecular biology; mycosphaerella graminicola pathosystem; Necrosis; Pathogens; Plant biology; Plant breeding; Plant Genetics and Genomics; plant height; Plant Pathology; Plant Physiology; Plant Sciences; Quantitative trait loci; Seedlings; Septoria tritici; Septoria tritici blotch; Wheat; Winter wheat; Septoria tritici blotch; Resistance; QTL; Epistasis
• ISSN: 1380-3743; 1572-9788
• DOI: 10.1007/s11032-011-9592-8

Breeding for resistance to Septoria tritici blotch (STB), caused by
Mycosphaerella graminicola
(anamorph:
Septoria tritici
), is an essential component in controlling this important foliar disease of wheat. Inheritance of seedling resistance to seven worldwide pathogen isolates has been studied in a doubled-haploid (DH) population derived from a cross between the field resistant cultivar Solitär and the susceptible cultivar Mazurka. Multiple quantitative trait locus (QTL) mapping revealed major and minor genetic effects on resistance as well as several epistatic relationships in the seedling stage. Solitär conferred resistance to isolate IPO323, governed by
Stb6
on chromosome 3A, as well as to IPO99015, IPO92034, Hu1 and Hu2 controlled by a QTL on chromosome arm 1BS, possibly corresponding to
Stb11
and minor QTL on chromosomes 1B, 3D, 6B and 7D. Resistance of Mazurka to IPO90015 and BBA22 was caused by a QTL located in a region on 4AL which harbours
Stb7
or
Stb12
. QTL specific to pycnidial coverage on 3B and specific to necrosis on 1A could be discovered for isolate IPO92034. Pairwise epistatic interactions were reliably detected with five isolates. Although their contributions to the total variance are generally low, the genotypic effect of the QTL by QTL interaction of 4AL (
Stb7
or
Stb12
) and 3AS (
Stb6
) made up almost 15% of disease expression. Altogether, the results suggest a complex inheritance of resistance to STB in the seedling stage in terms of isolate-specificity and resistance mechanisms, which have implications for marker-assisted breeding in an attempt to pyramid STB resistance genes.