开花后不同光周期条件下大豆农艺性状和品质性状的QTL分析

以开花期相近的181个大豆重组自交系(RIL)为材料，研究开花后不同光照长度对大豆主要农艺性状的影响，并在利用SSR标记构建大豆遗传图谱的基础上，分别在长日(16 h)和短日(12 h)条件下检测与主要农艺性状及其光周期敏感度(PS)相关的QTL。结果表明，开花后光照处理对大豆农艺性状和品质性状有较大影响，不同性状的光周期敏感度差异明显，株高＞主茎节数＞蛋白质含量、脂肪含量＞百粒重＞单株荚数＞蛋白质和脂肪总量。利用复合区间作图法检测到12个与株高、主茎节数、单株荚数、百粒重、蛋白质和脂肪总量等性状及各性状对开花后光周期处理的敏感度相关的QTL，分别定位于A1、A2、B1、B2、C1、D1a、F、L等8个连锁群上。其中，在短日条件下检测到4个QTL，可解释的遗传变异范围在11.37%~26.63%之间；在长日条件下检测到3个QTL，可解释的遗传变异范围在11.84%~27.85%之间；检测到5个与不同性状光周期敏感度有关的QTL，可解释相对应性状表型变异的范围在6.15%~21.44%之间。针对同一性状，未检测到在长日和短日条件下均起作用的主效QTL, 说明开花后光周期对大豆产量和品质性状相关基因的表达有较大影响。

QTL Mapping of Agronomic and Quality Traits in Soybean under Different Post-Flowering Photoperiods

Most of agronomic and quality traits of soybean (Glycine max L. Merr.) are quantitatively inherited, and sensitive to photoperiod. In this study, 181recombinant inbred lines (RIL) of F₁₀ generation were used to analyze the post-flowering photoperiod effects on yield and quality traits of soybean, and 129 SSR markers were used to map QTLs associated with the above traits under both long day (LD) and short day (SD) conditions and their photoperiod sensitivity (PS). The results showed that photoperiod greatly affected the performances of agronomic and quality traits of soybean, and the photoperiod sensitivity of the traits were plant height.node number on the main stem>protein content and oil content>100-seed weight>pod number per plant>total percentage of protein and oil. By using CIM (composite interval mapping) method, a total of 12 QTLs associated with the agronomic and quality traits and their sensitivity to the post-flowering photoperiod were identified and mapped on eight linkage groups including A1, A2, B1, B2, C1, D1a, F and L. Among the QTLs mentioned above, four were identified under SD and could explain 11.37%–26.63% of phenotypic variation, and three were identified under LD condition and could explain 11.84%–27.85% of phenotypic variation. The other five were associated with photoperiod sensitivity of various traits and could explain 6.15%–21.44% of phenotypic variation. For the same individual agronomic or quality trait, no major QTL was detected under both SD and LD, indicating that post-flowering photoperiod dramatically regulates the expression of genes determining yield and quality traits, and the agronomic and quality traits of soybean are sensitive to environmental factors. It was drawn that photoperiod sensitivity is a key index for adaptability improvement of soybean. For breeding elite varieties with ideal yield potential, quality and stress tolerance, the photoperiod-insensitive genes related to various traits should be explored and pyramided with other needed genes.