Photoperiod Trait: Insight in Molecular Mechanism for Growth and Maturity Adaptation of Soybean (glycine Max) to Different Latitudes

Soybeans cover a vast geographical region of 53 degrees N to 40 degrees S latitudes, but individual genotypes have a very narrow latitudinal adaptation of similar to 200 km due to photoperiodic limitations. Fourteen soybean maturity groups (MG0000-X) of Northern America have genotypes adapted to very long (MG0000) to short (X) day length conditions. Photoperiod not only affects flowering but other agronomic traits also. Several maturity genes have been mapped, and 12 genes related to the photoperiodic network (E1, E2, E3, E4, J, FT2a, FT5a, Tof5, Tof11, Tof12, Tof16 and Tof18) have been functionally characterized. The role of the paralogues of functionally characterized genes (Ens, COs, PRRs, FULs, SOCs and FTs) is being recently elucidated. Allelic diversity at photoperiodic loci confers latitude specific adaptation. Molecular models (common allelic combination present in an MG) have been developed for different MG using E genes but require refining by the addition of other functionally characterized genes to fully explain the flowering and maturity, especially in MGV to X. Three interacting modules PHYA-E1, GI-CO and miRNA-dependent have been developed to elucidate the flowering mechanism in soybean.