Application of 50K chip-based genetic map to QTL mapping of stem-related traits in wheat

Stem strength is critical for lodging resistance in wheat. The present study utilised a high-density genetic map generated with a 50K single-nucleotide polymorphism (SNP) chip to map quantitative trait loci (QTLs) for stem-related traits. The analysis involved 198 recombinant inbred lines (RILs) derived from the cross between bread wheat (Triticum aestivum L.) varieties Xinong1376 and Xiaoyan81. The RILs were planted in randomised complete blocks with two replicates at three locations. The constructed genetic map contained 13571 SNP markers spanning 3605.53 cM across the 21 wheat chromosomes. The genetic and physical positions of SNP markers in 28 linkage groups were approximately the same. Twelve major QTLs related to stem strength were detected for eight traits and were distributed on chromosomes 2D (three QTLs), 3A, 4B, 4D (three QTLs), 5A, 5B, 5D and 6B. Each QTL explained 0.6-34.6% of the phenotypic variation. Taking full advantage of the available resources for fine-mapping of these stable QTLs will benefit molecular marker-assisted breeding and facilitate the dissection of molecular regulatory mechanisms underlying the mechanical properties of the wheat stem.