Construction of SNP genetic maps based on targeted next-generation sequencing and QTL mapping of vital agronomic traits in faba bean (Vicia faba L.)

Owing to the limitation of a large genome size (similar to 13 Gb), the genetic and gene mapping studies on faba bean (Vicia faba L.) are lagging far behind those for other legumes. In this study, we selected three purified faba bean lines (Yundou 8137, H0003712, and H000572) as parents and constructed two F-2 populations. These two F-2 populations, namely 167 F-2 plants in Pop1 (Yundou 8137xH0003712) and 204 F-2 plants in Pop2 (H000572xYundou 8137), were genotyped using a targeted next-generation sequencing (TNGS) genotyping platform, and two high-density single nucleotide polymorphisms (SNP) genetic linkage maps of faba bean were constructed. The map constructed from Pop1 contained 5 103 SNPs with a length of 1 333.31 cM and an average marker density of 0.26 cM. The map constructed from Pop2 contained 1 904 SNPs with a greater length of 1 610.61 cM. In these two F-2 populations, QTL mapping identified 98 QTLs for 14 agronomic traits related to the flowers, pods, plant types and grains. The two maps were then merged into an integrated genetic linkage map containing 6 895 SNPs, with a length of 3 324.48 cM. These results not only lay the foundation for fine mapping and map-based cloning of related genes, but can also accelerate the molecular marker-assisted breeding of faba bean.