QTL Mapping for Adult-Plant Resistance to Powdery Mildew, Lodging Resistance, and Internode Length Below Spike in Wheat

Quantitative trait loci (QTLs) for adult-plant resistance (APR) to powdery mildew, lodging resistance (LDR), and the internode length below spike (ILBS) in wheat (Triticum aestivum L.) were studied using a set of 168 doubled haploid (DH) lines derived from the cross between Huapei 3 and Yumai 57. A genetic linkage map was constructed using 305 simple sequence repeat (SSR) markers. The DH population and the parents were evaluated for APR to powdery mildew, LDR, and ILBS in 2005 and 2006 growing seasons in Tai'an, Shandong Province and in 2006 growing season in Suzhou, Anhui Province, China. QTL analysis was performed using the software of QTLNetwork version 2.0 based on the mixed linear model. A total of 12 additive QTLs and 10 pairs of epistatic QTLs were detected for APR to powdery mildew, LDR, and ILBS. QTL qApr4D was detected for APR to powdery mildew on chromosome 4D with an increased effect on resistance. The QTL was from Yumai 57, which explained 20.0% of the phenotypic variances without additive × environment (AE) interactions. QTL qIlbs7D was identified for ILBS on chromosome 7D, explaining 12.9% of the phenotypic variances without AE interactions. Both additive and epistatic effects are important genetic bases for APR to powdery mildew, LDR, and ILBS, and are sometimes subjected to environmental modifications. The 2 QTLs mentioned earlier are applicable in marker-assisted selection for APR to powdery mildew and ILBS in wheat breeding programs.