【作者】 高美玲；

【导师】 栾非时；

【作者基本信息】 东北农业大学 ， 蔬菜学， 2011， 博士

【摘要】 甜瓜（Cucumis melo L.）,2n=2x=24,为葫芦科（Cucurbitaceae）甜瓜属（Cucumis Linn）一年生草本植物,是国内外重要的园艺作物和经济作物,中国甜瓜种植面积和产量均居世界第一位。现有的甜瓜品种大多数为雄全同株类型,即植株上有单性的雄花和两性花,其中能结果的是两性花,在制杂种一代时必须去雄,使甜瓜F1代制种成本是传统品种的12-30倍,而利用纯雌系制一代杂种无需去雄,节约劳动力,可大大降低制种成本。因此,本项目开展甜瓜纯雌株及雌花相关性状,即第一雌花开花期（DFF）、雌花率（RF）、雌花连生类型（MNF）、第一雌花节位（NFF）,遗传分析及其基因定位的研究,以期为甜瓜纯雌系选育提供更多依据。以美国纯雌株厚皮甜瓜品系WI998（AAgg）为母本,中国雌雄异花同株薄皮甜瓜品系3-2-2（AAGG）为父本,构建了六世代群体（P1、P2、F1、F2、BC1P1、BC2P2）,田间调查各世代性别分化类型和NFF性状进行遗传分析,结果显示：F1全部为雌雄异花同株,F2群体中雌雄异花同株与纯雌株的分离比为3：1,BC1P1群体中雌雄异花同株与纯雌株比例为1：1,BC1P2全部为雌雄异花同株,可见纯雌株性状为一对隐性基因控制的质量性状。NFF性状不符合孟德尔遗传,在F2群体中呈连续分布,可见此性状为数量性状。以WI998和3-2-2为亲本,通过单粒传构建了含有185个家系的F6：7重组自交系（RILs）分离群体,调查此群体春秋两季雌花相关性状（DFF、RF、MNF、NFF）,运用RILs群体主基因+多基因模型进行遗传分析,结果显示：RF和MNF性状不存在这些模型所对应的基因效应。DFF春秋两季最优模型均为2对主基因+加性多基因遗传模型（E₁₈）,春秋两季主基因遗传率分别为77.05%,72.38%,多基因遗传率分别为22.44%,27.52%；NFF性状遗传春季最优模型为E₁₈模型,秋季最优模型为E₁₇,主基因遗传率分别为79.17%,61.94%,多基因遗传率分别为20.83%,36.77%。选用了1219对SSR引物,以RILs群体（WI998×3-2-2）为作图群体,构建了甜瓜永久遗传图谱,在亲本间有多态性的引物有215对,多态率17.6%,图谱共包含210个SSR标记,分属18个连锁群,覆盖基因组长度为937.1cM,标记间平均距离为4.4cM,该图谱是以SSR共显性标记为框架的甜瓜永久遗传图谱,且本图谱定位了新的SSR标记,为后续图谱加密整合及性状定位奠定了基础。在永久遗传图谱基础上,结合RILs群体性别类型的田间调查数据,将纯雌性基因（g）定位到了第1连锁群上,其两侧标记为NR3和MU8294₁,与g基因的遗传间距分别为1.2cM和2.6cM。NR3标记是筛选到距离g基因最近的SSR标记,有助于在育种中采用标记辅助选择甜瓜性别类型。W1998与3-2-2杂交的重组自交系群体雌花率和雌花连生类型分离表明这两个性状由一对基因控制,并将雌花率基因（rf1）和雌花连生类型基因（mnf）定位到第1连锁群上,雌花率基因（rf1）两侧的标记为g和MU8294-1,距离rf因的距离为0.6 cM和2 cM,同时还检测到一个控制雌花率的微效基因（rf2）,雌花连生类型基因（mnf）两侧的标记为MU11132和CMBR078,距离mnf因的距离分别为0.3cM和5.8cM。以永久图谱为基础,结合RILs群体家系雌花相关性状春秋两季田间调查的的数据,分别于春秋两季进行了QTL定位,结果显示：1.与雌花相关的性状（DFF、NFF）在F6：7/春与F6：7/秋两季共检测到5个QTL,第1连锁群上检测到的位点较多,出现了QTL位点相对聚集的现象。2.DFF性状春秋两季各检测到了1个QTL位点（qdff1.2, LOD=6.81, R2=32.40%,春；qdff1.1, LOD=5.82, R2=39.20,秋）,贡献率均高于10%,而且加性效应均为负值（春,-22.74；秋,-22.06）。2.NFF春秋两季共检测到3个QTL位点,春季检测到的2个位点（qnff7.1, qnff8.1）分别位于第7和第8连锁群上,加性效应均为负值（-0.22,-0.29）,贡献率分别为6.78%（LOD=2.17）,11.04%（LOD=2.36）；秋季检测到的位点qnf1.1与春季检测到的第一雌花开花期位点（qdff1.2）位于第1连锁群的相同位置。本研究中遗传图谱的建立及纯雌性基因的定位为甜瓜高密度遗传连锁图谱的构建、甜瓜纯雌系分子标记辅助选择育种提供理论依据。另外,雌花相关性状的遗传分析及QTL定位为更全面了解甜瓜雌花形成提供参考信息。更多还原

【Abstract】 Melon （Cucumis melo L.）,2n=2x=24, is a very important economically horticultural crop worldwide, belonging Cucurbitaceae family. The land area cultivated melon in China is first widely and production is first in the world. Andromonoecy is a widespread sexual system in cultivar melon characterized by plants carrying both male and bisexual flowers, only which can fruit. So, producing melon-generation hybrid through emasculation by measures cost higher than conventional varieties 12-30 times. And used gynoecious without emasculation will save labor, reduce the price of produced seeds. So, in order to provide the basis for breeding melon gynoecious line, genetic analysis of the gynoecious and femle sex related traits, days of first female flower（DFF）, rate of female flower（RF）, maximum number of female in secondary branches（MNF）, node number of first female flower（NFF）, were studied, and mapping their genes.In this study, the homozygous monoecious line 3-2-2 （AAGG） from China, thin-skinned, was crossed with the homozygous gynoecious line WI998 （AAgg）, thick-skinned from USA to get six generations（P1、P2、F1、F2、BC1P1、BC1P2）, which were used to reseach the genetic analysis of gynoecious and NFF. The results were as follows:F1 plants were all monoecious. The segregation ratio of monoecious and gynoecious was 3:1 in F2 population. The segregation ratio of monoecious and gynoecious is 1:1 in BC1P1 population. Monoecious phenotype was conferred by the dominant allele of the gynoecious （g） gene, whereas recessive homozygous plants are gynoecious. Number of plants of NFF was continues distribution in F2 population, so inheritance of NFF was quality trait.The F1 between 3-2-2 and WI998 was self-pollinated to produce F2 progeny, which were then self-pollinated by single-seed descent （SSD） to obtain 185 F6:7 recombinant inbred lines （RILs）. The data of DFF、RF、MNF、NFF were collected in F6:7/spring and F6:7/autumn. Inheritance model of major gene plus polygene for RILs population was used to the data analysis. The results were as follows:RF and MNF traits did not have these models of the corresponding gene effect. The optimal model for DFF was two major genes plus additive polygene model （E₁₈） in spring and autumn. hmg2 was 77.05%,72.38% in spring and autumn, respectively. hpg2 was 22.44%,27.52% in spring and autumn, respectively. The optimal model for NFF was two major genes plus additive polygene model （E₁₈） in spring, hmg2 was 79.17%, hpg2 was 20.83%, respectively. And model E₁₇ was optimal for NFF in autumn, hmg2 was 61.94%, hpg2 was 36.77%, respectively.1219 simple repeated sequences （SSRs） markers were used to amplify parental DNA for polymorphism detection.215 （17.6%） were polymorphic between two parental lines and were used in linkage analysis in RILs population. The resulting genetic map consisted of 18 linkage groups spanning 937.1 cM with a mean marker interval of 4.4 cM. This melon genetic map framework was SSR codominant markers, providing the basis for map integration and trait mapping.The segregation ratio of RF and MNF was 1:1 in RIL population, respectively. RF and MNF phenotype was conferred by an allele of the RF （rf） and MNF （mnf） gene, respectively. Based on the RILs linkage map and RE and MNF data, the g and SSR markers MU8294₁ were mapped near the rf locus at 0.6 cM and 2 cM in linkage group 1, respectively, and RF minimum gene （rf2） were mapped; the SSR markers MU11132 and CMBR078 were mapped near the mnflocus at 0.3 cM and 5.8 cM in linkage group 1, respectively.Based on the RILs linkage map and sexual type data, the SSR markers NR3 and MU8294₁ were mapped near the g locus at 1.2 cM and 2.6 cM in linkage group 1, respectively. Marker NR3 was the closest to the g gene identified, and can be useful in breeding programs, using marker-assisted selection procedures to screen for sexual type in melon.Based on the RILs linkage map, the QTL analysis of the female sex related traits was done in F6:7families between two seasons. The results were as follows:1. Five QTL were detected for four female sex related traits（DFF、NFF） in F6:7/autumn and F6:7/spring. QTL appeared relatively aggregation of sites in LG1.2. One QTL were detected for DFF trait in spring and autumn, respectively（adff1.2, LOD=6.81, R2=32.40%, spring; qdff1.1, LOD=5.82, R2=39.20, autumn）, R2 >10%, both additive values were negative.3. Three QTL were detected for NFF trait in spring and autumn. Two QTL （qnff7.1, R2=6.78%, LOD=2.17; qnff8.1, R2= 11.04%, LOD=2.36） in LG7 and LG8 in spring, both additive effect values were negative（-0.22,-0.29）. qnff1.1 detected for NFF trait in autumn and qdff1.2 detected for DFF trait in spring in the LG1 same region.In this study, the construction of genetic maps and gynoecious localization provide a theories basis for construction of the high-density genetic linkage map and melon gynoecious lines molecular marker assisted breeding. In addition, genetic analysis and QTL mapping of female-related traits contribute to more comprehensive understanding melon female development.更多还原