夏大豆重组自交系群体遗传图谱构建及开花期QTL分析

【背景】开花期是大豆重要的生育期性状,不仅决定了大豆品种的适种范围,而且对大豆的产量和品质有重要影响。江淮地区是中国重要的大豆产区,目前对该地区夏大豆开花期性状遗传基础研究相对较少。【目的】利用2个夏大豆材料杂交衍生的重组自交系群体对开花期进行QTL定位,为分子标记辅助选择育种和基因克隆提供依据。【方法】以科丰35(KF35)和南农1138-2(NN1138-2)为亲本,构建了含91个家系(F2:8)的重组自交系群体(NJK3N-RIL),在6个环境下调查开花期性状数据。利用限制位点相关DNA测序(restriction-site associated DNA sequencing,RAD-seq)技术对群体亲本及家系材料进行SNP标记分型,并利用窗口滑动法进行bin标记划分。利用bin标记构建该群体的遗传图谱,结合多年多点的表型数据,使用QTL Network 2.2软件中的基于混合线性模型的复合区间作图法(mixed-model based composite interval mapping,MCIM)和Windows QTL Cartographer V2.5₀

Construction of Genetic Map and Mapping QTL for Flowering Time in A Summer Planting Soybean Recombinant Inbred Line Population

【Background】 Flowering time (FT) is an important agronomic trait, which determines the planting range of cultivars and has a significant influence on the yield and quality of soybean. The Chinese Jiang-Huai valley is an important soybean producing area. However, little is known about the genetic basis of flowering time in these genotypes. 【Objective】 The objectives of this study were to map mapping quantitative trait loci (QTLs) and identify stable and reliable loci that can be used for molecular marker-assisted selection (MAS) and map-based gene cloning, and then dissect the genetic basis of flowering time in summer planting soybean. 【Method】 A recombinant inbred lines (RIL) population containing 91 lines (F_2:8) developed by crossing KF35 with NN1138-2 was planted in six environments to investigate phenotypic data. Restriction-site associated DNA sequencing (RAD-seq) technology was used to genotype all lines and their parents. And then bin markers were obtained by window sliding method based on the SNP markers and used to construct the genetic map. The mixed-model based composite interval mapping (MCIM) method in the software of QTL Network 2.2 and the composite interval mapping (CIM) method in the software of Windows QTL Cartographer V2.5_011 were used to reveal the effects of the QTLs of FT. 【Result】 A total of 36778 high-quality SNP markers were obtained in the whole soybean genome, and further divided into 1733 bin markers. A high-density genetic map with 1733 bin markers was constructed that spanned 2362.4 cM of the soybean genome with an average marker distance of 1.4 cM. Nine additive QTLs, two pairs of epistatic QTLs and one environmental interaction QTL were detected by MCIM method. The cumulative contribution of additive, epistatic and environmental interaction effects were 63.9%, 4.6% and 2.1%, respectively. Ten QTLs were detected by CIM method, and four of them, qFT-8-1, qFT-11-1, qFT-15-1 and qFT-16-1 could be detected in three or more environments. Altogether, 12 QTLs controlling FT were mapped using MCIM and CIM methods. Six of them, qFT-8-1, qFT-11-1, qFT-15-1, qFT-16-1, qFT-16-2, qFT-20-1 and qFT-20-2 could be detected by two methods. Six novel QTLs, qFT-5-1, qFT-8-1, qFT-8-2, qFT-13-1, qFT-15-1 and qFT-20-2 were detected in this study. 【Conclusion】 The genetic composition of FT in summer planting soybean is relatively complex. However, the additive effect was dominant, epistatic interaction and environmental interaction had little effect on FT. Four QTLs, qFT-8-1, qFT-11-1, qFT-15-1 and qFT-16-1 can be detected by two methods and in multiple environments, which are important loci for controlling FT in NJK3N-RIL population.