Mapping of QTL and candidate genes associated with powdery mildew resistance in triticale (× Triticosecale Wittm.)

Modern triticale breeding is focusing on combining biotic and abiotic stress resistance. Cultivation of varieties resistant to fungal pathogens is an economically and environmentally beneficial means and may lead to reducing the use of fungicides. Molecular markers are necessary for accumulation of advantageous alleles in the best genotypes by means of marker-assisted and genomic selection approaches. In present research, quantitative trait loci (QTL) associated with powdery mildew resistance at the adult plant stage were evaluated in order to provide effective selection tools. Testing of the 'Hewo' x 'Magnat' DH population in multiple environments under natural infestation revealed 20 QTL on three wheat (4A, 3B, 4B) and four rye (2R, 4R, 5R, 6R) chromosomes. QTL explained 8.1%–29.3% of phenotypic variation depending of the trait, location and year of the experiment. Main QTL with effect exceeding 15% were found on chromosomes 3B, 4B, 2R, 5R and 6R. QTL and candidate genes located on chromosomes 4B, 2R, 5R and 6R were reported for the first time. Additionally, for all QTL, 21 candidate genes associated with the PM resistance were revealed. Predicted function of protein encoded by these genes include triggering a defense system which restricts the pathogen growth as well as enzyme activity, regulation of hormone-activated pathways, transcriptional corepressor complex and cell wall construction. Availability of QTL, molecular markers together with candidate genes linked with the powdery mildew resistance can be validated on triticale lines and varieties and then used in marker-assisted selection to improve breeding of triticale.