菜心遗传图谱构建及主要农艺性状的QTL定位

发布时间：2018-08-17 19:48

【摘要】：菜心是华南地区栽培面积最大的特色蔬菜之一,优质、抗逆和丰产性状是菜心育种的主要目标。随着分子标记技术的发展,遗传连锁图谱的构建、基因定位已成为作物遗传和分子育种研究和应用工作的重要部分,研究开发出的与目标性状紧密连锁的分子标记可加快品种选育进程。据此,本研究以菜心材料“3T6”和“四九-19号菜心”为父母本构建的130份重组自交系(RIL)群体为材料,利用简单重复序列(SSR)标记构建了一张覆盖10个连锁群的菜心遗传图谱,并结合菜心RIL群体一些主要农艺性状的测定数据,对这些农艺性状进行数量性状基因座(QTL)定位和分析。研究结果如下:通过对来自于菜心转录组测序开发的790对SSR引物和多国芸薹属基因组计划芸薹属数据库中的160对SSR标记的引物组合进行筛选,获得了212对在菜心亲本“3T6”和“四九-19号菜心”间PCR扩增产物条带清晰、重复性好且具有多态性的SSR引物组合。利用这些具有多态性的SSR标记,对菜心RIL群体进行基因分型,得到了283个等位变异位点。根据菜心RIL群体间存在的等位变异数据,运用MapMaker 2.0软件,构建出一张覆盖菜心10个连锁群、长1723.81 cM的菜心遗传图谱。该图谱包含197个等位变异位点,平均图距为8.75 cM。根据已知的芸薹属通用SSR锚定引物在染色体上的位置,初步确定了这10个连锁群与菜心染色体的对应关系。另外,研究发现图谱中197个变异位点中有114个位点发生了偏分离,其中偏向父本“3T6”的有75个,占全部偏分离位点的65.79%;偏向母本“四九-19号菜心”的有39个,占偏分离位点总数的34.21%。并且发现17个偏分离热点区域(SDR),分布在9条染色体上。其中A10染色体上最多,具有3个SDRs;A1、A2、A3、A5、A7和A9染色体上各有2个SDR;而A6和A8染色体则分别只有1个SDR。在已经构建的遗传图谱的基础上,依据2015~2016年2年田间试验测定RIL群体各株系的株高、开展度、株重、薹高、薹粗、最大叶叶长、最大叶叶宽、最大叶叶柄长、最大叶叶柄宽、基叶数、薹叶数和与叶绿素含量相关的SPAD值等13个农艺性状数据,运用QGene 2.30软件,对这些农艺性状进行QTL定位,共发现29个解释表型变异的贡献率在8.5~30.3%之间QTLs。这些QTLs分别位于A1、A4、A5、A6、A7、A8、A9和A10等8条染色体上,其中与最大叶叶宽相关的QTL数最多,为5个;其次为SPAD值,具有4个QTLs;控制最大叶叶长和薹重相关的QTL各3个,与开展度、最大叶叶柄长、最大叶叶柄宽、薹粗和株重相关的QTLs各2个,与株高、基叶数、薹叶数和薹高相关的QTL则各1个。此外,检测到株重、最大叶叶长和最大叶叶宽均存在1个多次试验均检测到解释的表型变异的贡献率在10%的QTL位点。研究结果可为菜心分子标记辅助育种提供参考。
[Abstract]:Cauliflower is one of the largest cultivated characteristic vegetables in South China. High quality, stress resistance and high yield are the main objectives of vegetable heart breeding. With the development of molecular marker technology and the construction of genetic linkage map, gene mapping has become an important part of the research and application of crop genetics and molecular breeding. The development of molecular markers closely linked to the target traits can accelerate the breeding process. On the basis of this, a genetic map of 10 linkage groups was constructed from 130 recombinant inbred lines (RIL) population constructed by parents of "3T6" and "49- 19" as parents, using simple repeat sequence (SSR) markers. The quantitative trait loci were mapped and analyzed by (QTL) combined with the data of some main agronomic characters in RIL population of Chinese cabbage. The results were as follows: by screening 790 pairs of SSR primers and 160 pairs of SSR marker primer combinations from the Brassica Genome Project database, which were developed by sequencing the transcripts of cauliflower, 790 pairs of primers were selected. 212 pairs of SSR primer combinations with clear bands, good reproducibility and polymorphism were obtained between the parents of Chinese cabbage "3T6" and "49- 19". Using these polymorphic SSR markers, the alleles of RIL population were genotyped and 283 alleles were obtained. Based on the allelic variation data among RIL populations, a genetic map covering 10 linkage groups and 1723.81 cm in length was constructed by using MapMaker 2.0 software. The map contains 197 allelic variation sites with an average map distance of 8.75 cm. Based on the known position of common SSR anchoring primers on chromosomes of Brassica, the corresponding relationship between the 10 linkage groups and the chromosomes of Chinese cabbage was preliminarily determined. In addition, the study found that 114 of the 197 variant loci in the map showed partial segregation, of which 75 were in favor of the male parent "3T6", accounting for 65.79% of the total partial segregation sites, and 39 were inclined to the female parent "49- 19". It accounts for 34.21% of the total number of segregation sites. It was also found that the (SDR), of 17 partial segregation hotspots were distributed on 9 chromosomes. There were two SDRs on A10 chromosome, two SDRs on A9 chromosome and one SDRs on A6 and A8 chromosomes, respectively. Based on the genetic map that has been constructed, the plant height, development degree, plant weight, bolting height, bolting diameter, leaf length, leaf petiole width, leaf stem width, stem width and stem width of RIL population were determined by field experiments from 2015 to 2016. The data of 13 agronomic characters, such as basal leaf number, bolting leaf number and SPAD value related to chlorophyll content, were mapped by QTL using QGene 2.30 software. A total of 29 explained phenotypic variation rates were found to be in the range of 8.5% or 30.3%. These QTLs were located on 8 chromosomes A1, A4, A4, A5, A6, A7, A8, A9, A10, respectively. The QTL numbers associated with the maximum leaf width were 5, followed by SPAD, with 4 QTLs, and QTL, which controlled the maximum leaf length and bolting weight, respectively, and the degree of development. The QTLs of maximum petiole length, maximum petiole width, bolting diameter and plant weight were 2, respectively, and QTL with plant height, basal leaf number, bolting leaf number and bolting height were 1, respectively. In addition, the plant weight, the maximum leaf length and the maximum leaf width were detected at 10% of the QTL site, which accounted for 10% of the phenotypic variation in multiple experiments. The results can provide reference for molecular marker-assisted breeding of Chinese cabbage.
【学位授予单位】：广州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S634.5

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