Rapid identification of consistent novel QTLs underlying long-juvenile trait in soybean by multiple genetic populations and genotyping-by-sequencing.

Flowering time is an important factor that controls crop yield and latitudinal adaptation. Soybean is a facultative short-day (SD) plant, and cultivars that originate from temperate regions generally undergo a very short juvenile phase and early flowering when grown in low-latitude regions, thereby resulting in extremely low grain yield. However, introduction of the long-juvenile (LJ) trait, which extends the vegetative phase and improves yield under SD environments, has largely overcome this constraint and has enabled the expansion of soybean production to tropical regions. Quantitative trait locus (QTL) mapping is a fundamental approach to the identification of new loci related to LJ trait, while conventional strategy takes lots of time to verify the findings. Here, we provide a new strategy to rapidly identify consistent novel QTLs by using multiple genetic populations and genotyping-by-sequencing (GBS) approach. In this study, we developed six F₂ populations and grew them under SD conditions. A total of seven QTLs related to the LJ trait were identified by integrating flowering time (R1) and high-density genetic maps. There were three consistent QTLs repeatedly detected in different populations and one of them has been previously reported, yet two are novel. This research not only provides fundamental resources for fine-mapping candidate genes associated to the LJ trait, but also provides new insights to QTL mapping. [ABSTRACT FROM AUTHOR]