Mutagenesis of GmFT2a and GmFT5a mediated by CRISPR/Cas9 contributes for expanding the regional adaptability of soybean

Summary Flowering time is a key agronomic trait that directly influences the successful adaptation of soybean ( Glycine max ) to diverse latitudes and farming systems. Gm FT 2a and Gm FT 5a have been extensively identified as flowering activators and integrators in soybean. Here, we identified two quantitative trait loci ( QTL s) regions harbouring Gm FT 2a and Gm FT 5a , respectively, associated with different genetic effects on flowering under different photoperiods. We analysed the flowering time of transgenic plants overexpressing Gm FT 2a or Gm FT 5a , ft2a mutants, ft5a mutants and ft2aft5a double mutants under long‐day ( LD ) and short‐day ( SD ) conditions. We confirmed that Gm FT 2a and Gm FT 5a are not redundant, they collectively regulate flowering time, and the effect of Gm FT 2a is more prominent than that of Gm FT 5a under SD conditions whereas Gm FT 5a has more significant effects than Gm FT 2a under LD conditions. Gm FT 5a , not Gm FT 2a , was essential for soybean to adapt to high latitude regions. The ft2aft5a double mutants showed late flowering by about 31.3 days under SD conditions and produced significantly increased numbers of pods and seeds per plant compared to the wild type. We speculate that these mutants may have enormous yield potential for the tropics. In addition, we examined the sequences of these two loci in 202 soybean accessions and investigated the flowering phenotypes, geographical distributions and maturity groups within major haplotypes. These results will contribute to soybean breeding and regional adaptability.