High-Resolution Bin Maps Provide Insights for QTL Mapping of Yield-Related Traits with Milyang23/Gihobyeo Recombinant Inbred Lines

High-throughput genotyping has substantially advanced the quality and accuracy of single nucleotide polymorphism (SNP) discovery and provided an effective way to interpret phenotypic variations in a mapping population. High-resolution quantitative trait locus (QTL) mapping is important for understanding agricultural traits. However, constructing a high-resolution map without sufficient markers to detect QTLs/genes of agronomically important traits is laborious and time consuming. In this study, 160 recombinant inbred lines (RILs) derived from a cross between Milyang23 and Gihobyeo were re-sequenced, and their SNPs were used for high-resolution QTL mapping of yield-related traits. A total of 1,850,671 high-quality SNPs from RILs were detected, and 3,563 bins were used as genetic markers to construct a high-resolution genetic map using the sliding window approach. The total genetic distance was 1,278.62 cM. Using the QTL analysis, we identified 35 QTLs controlling six yield traits, namely, culm length, panicle length, panicle number per plant, primary branch number per panicle, grain number per plant, and 100-grain weight. In addition, we detected major QTLs associated with culm length and grain number, and compared their physical distances using a conventional genetic map. These results showed that rapid, high-resolution QTL mapping using high-quality SNPs as bin markers is a powerful tool for finemapping and cloning important QTLs/genes.