Inheritance of field resistance to Septoria tritici blotch in the wheat doubled-haploid population Solitär × Mazurka

• Published in: Euphytica 2013-11, Vol.194 (2), p.161-176
• Main Authors: Kosellek, Christiane, Pillen, Klaus, Nelson, James C., Weber, W. Eberhard, Saal, Bernhard
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Biomedical and Life Sciences; Biotechnology; Chromosomes; Cultivars; Field tests; Fundamental and applied biological sciences. Psychology; Genetics and breeding of economic plants; Genotype & phenotype; Haploidy, in vitro culture applications, somatic hybrids; Life Sciences; Plant breeding: fundamental aspects and methodology; Plant diseases; Plant Genetics and Genomics; Plant Pathology; Plant Physiology; Plant populations; Plant resistance; Plant Sciences; Selective breeding; Wheat
• ISSN: 0014-2336; 1573-5060
• DOI: 10.1007/s10681-013-0898-y

Breeding for field resistance to Septoria tritici blotch (STB), caused by Mycosphaerella graminicola (anamorph: Septoria tritici ), is the most suitable strategy for controlling this important disease of wheat. Although many Stb genes for resistance to single pathogen isolates have been identified in wheat, knowledge of their efficiency against natural fungal populations is lacking. In a quantitative-trait-locus (QTL) mapping approach in six environments and four locations, field resistance to STB was studied in a doubled-haploid population derived from a cross between the field-resistant cultivar Solitär and the susceptible cultivar Mazurka. After plant height as a disease escape trait was accounted for, five QTL with effects on STB response on chromosomes 5A, 6D and 7D explained 20 % of the genotypic variance; QTL  ×  environment interactions were minor. Field resistance was conferred exclusively by alleles from Solitär, which was previously shown to carry the isolate-specific genes Stb6 and Stb11 as well as minor QTL detected with seven fungal isolates. Surprisingly, neither the Stb6 nor Stb11 isolate-specific genes nor minor QTL previously detected in Solitär were found to be involved in its field resistance. The study suggests that resistance breeding for STB should not rest solely on the deployment of Stb genes. Field tests are indispensable to show their efficacy and durability and to identify genes conferring partial field resistance to STB.