陆地棉高密度遗传图谱的构建及产量相关性状的QTL定位

【目的】通过构建高密度SNP遗传图谱,开展棉花多群体产量相关性状的QTL定位,获得稳定性好、精确度高的QTL,为产量性状调控基因的挖掘和有效分子标记的开发提供依据。【方法】以高稳产冀丰1271为母本、优质自交系冀丰173为父本,构建包含200个单株的F₂群体,利用测序基因分型(genotyping by sequencing,GBS)技术开发群体的SNP标记并构建高密度遗传图谱,对F₂、F_2:3、F_2:4群体的衣分、子指和单铃重进行QTL定位,注释主效和稳定QTL位点内的基因并分析基因在不同组织的表达模式,筛选候选基因。【结果】通过简化基因组测序,共获得383.07 Gb数据,包括母本冀丰1271的26.93 Gb、父本冀丰173的27.30 Gb和F₂群体的328.84 Gb,Q30值分别为90.55%、89.95%和95.77%。在F₂群体中开发了1 305 642个SNP标记,其中,用于构建遗传图谱的aa?bb型SNP为410 726个。构建了一张包...

Construction of A High-Density Genetic Map and QTL Mapping for Yield Related Traits in Upland Cotton

【Objective】By constructing a high-density SNP genetic map, QTL mapping for cotton yield related traits of multiple populations was carried out to obtain stable and accurate QTL. It will provide references for the excavation of yield trait regulatory genes and the development of effective molecular markers. 【Method】Jifeng 1271 with high and stable yield and Jifeng173 with super fiber quality were used to construct an F₂ population composing of 200 plants. A high-density SNP genetic map was constructed by GBS (Genotyping by sequencing), and QTL mapping was carried out for lint percentage, seed index and boll weight of F₂, F_2:3 and F_2:4 populations. Genes in major and stable QTL were annotated, and the expression patterns in different tissues were analyzed for candidate genes selection. 【Result】A total of 383.07 Gb data was obtained by GBS, including 26.93 Gb for the maternal cultivar Jifeng 1271, 27.30 Gb for the paternal inbred line Jifeng 173 and 328.84 Gb for the 200 F₂ plants, and Q30 scores were 90.55%, 89.95% and 95.77%, respectively. And 1 305 642 SNP markers were developed in the F₂ population, including 410 726 aa×bb type SNP that were used for genetic map construction. A high-density genetic map containing 16 088 SNP and spanning 4 282.81 cM was constructed, and the average genetic distance between adjacent SNP was 0.27 cM. Collinearity analysis proved high quality of the genetic map. A total of 108 yield related QTL were mapped, including 34 lint percentage QTL, 36 seed index QTL and 38 boll weight QTL. 30 QTL overlapped with or were close to the published QTL, and the other 78 QTL were new. 10 major QTL and 16 stable QTL were found, and 5 major QTL could be mapped in 2 or 3 populations. qLP-A13-4 could be mapped in 3 populations, and the R² reached 13.78%. qLP-A13-6 could be mapped in 2 populations, and the R² reached 10.01%. qLP-D10-2 could be mapped in 2 populations, and the R² reached 10.92%. qSI-D10-1 could be mapped in 2 populations and the R² reached 12.31%. qBW-D5-3 could be mapped in 2 populations and the R² reached 15.54%. A total of 3 415 genes were annotated in these major and stable QTL. By KEGG and GO analysis, the annotated genes are mainly involved in plant hormone signal transduction, TCA cycle, biosynthesis of secondary metabolites and amino acids, carbon fixation in photosynthetic organisms. Using the transcriptome data of TM-1 and NDM8, 8 genes were highly expressed in fiber, ovule or seed, which may be important candidate genes for boll weight and yield by regulating lint percentage or seed index. 【Conclusion】An intra-specific high-density genetic map was constructed for upland cotton. 108 yield related QTL were mapped, 5 major QTL could be mapped in at least 2 populations, and 8 candidate genes with high expression level in fiber, ovule or seed were identified.