背景回顾：The classical soybean (Glycine max) trait long juvenile (LJ) is essentially a reduction in sensitivity to short-day (SD) conditions for induction and completion of flowering, and has been introduced into soybean cultivars to improve yield in tropical environments. 

提出问题：However, only one locus, J, is known to confer LJ in low-latitude varieties. 

主要发现：Here, we defined two quantitative trait loci contributing to the LJ trait, LJ16.1 and LJ16.2, and identified them as the florigen (FT) homologs FT2a and FT5a, respectively. 

结果1-突变表型：The two selected florigen variations both delay flowering time under SD conditions by repressing the floral meristem identity gene GmAPETALA1. 

结果2-遗传补偿：Single mutants have a relatively subtle effect on flowering time and displayed a substantial genetic compensation response, but this was absent in ft2a ft5a double mutants, which showed an enhanced LJ phenotype that translated to higher yields under SD conditions. 

结果3-适应性演化：A survey of sequence diversity suggests that FT2a and FT5a variants have diverse origins and have played distinct roles as soybean spread to lower latitudes. 

结论：Our results show that integration of variants in the florigen genes offers a strategy for customizing flowering time to adjust adaptation and improve crop productivity in tropical regions.

 摘 要 

大豆（Glycine max）的性状长童期实质上是降低对短日照条件诱导开花的敏感性，已被引入大豆栽培种中以提高其在热带环境下的产量。然而，目前只知道一个位点J赋予了低纬度大豆品种的长童期。本文中，作者鉴定了两个影响大豆长童期性状的数量性状基因座LJ16.1和LJ16.2，并进一步鉴定到了其关键基因分别为FT同源基因FT2a和FT5a。在短日照条件下，FT2a和FT5a的突变均会通过抑制花分生组织决定基因GmAP1而延迟开花。单个基因的突变对开花时间的影响相对较小，并表现出明显的遗传补偿效应，但在ft2a ft5a双突变体中没有遗传补偿效应，因此表现出增强的长童期表型，即在短日照条件下的产量更高。对序列多样性的研究表明，FT2a和FT5a变体具有不同的起源，并在大豆向低纬度地区扩散的过程中发挥了不同的作用。本文的研究结果表明，整合不同成花基因的变异提供了一种能够定制开花时间的策略，以调整作物在热带地区的适应性及产量提升。

 通讯作者 

** 刘宝辉 **