【作者】 沈镝；

【导师】 方智远；

【作者基本信息】 中国农业科学院 ， 蔬菜学， 2009， 博士

【摘要】 西双版纳黄瓜（Cucumis sativus L.var.xishuangbannanesis Qi et Yuan）是我国特有的黄瓜变种,老瓜果肉橙黄是异于普通黄瓜的主要特异性状。本研究对30份西双版纳黄瓜种质资源的5个质量性状和13个数量性状进行形态鉴定,并以其273个单株样本为研究对象,利用SSR技术从群体水平分析其遗传多样性;分析测定了18份达到生理成熟度的不同类型版纳黄瓜的主要类胡萝卜素种类和含量等营养成分。以其中2份版纳黄瓜种质为试材,分析果实成熟期主要类胡萝卜素、维生素C和可溶性糖含量的变化规律。采用分期播种分析温光条件对这2份种质性型分化的影响;利用主基因+多基因混合遗传模型联合分析方法,对两个组合P₁、P₂、F₁和F₂四世代材料的老瓜果肉色相关指标进行遗传规律研究;以版纳黄瓜为构图亲本构建了黄瓜SSR分子遗传连锁图谱,并对老瓜果肉色、性型、成株白粉病抗性等重要性状进行QTL定位分析。主要研究结果如下:1.30份版纳黄瓜种质在形态水平具有一定的遗传多样性。与性型分化和侧枝发生相关的5个数量性状的差异较大,变异系数较高,子叶长等8个性状差异不明显。基于形态性状的聚类分析结果与版纳黄瓜的重要农艺性状基本吻合。2.SSR分析结果显示273个样本的多态位点百分率、Nei’s基因多样性指数（H）和Shannon’s信息指数（I）分别为92.86%、0.1818和0.2972。30份种质的聚类分组结果与瓜皮色和果肉色等性状基本一致。按不同来源地将种质分为5个群体,以景洪群体的遗传多样性最高,群体间基因分化不明显,基因交流基本顺畅。3.版纳黄瓜的侧蔓发生及性型分化的变化与外界环境的温度和光照关系密切,2份种质的雌花分化与侧蔓发生呈明显相反的变化趋势。版纳黄瓜是对低温、短日照十分敏感的黄瓜种质类型,在北京地区保护地栽培的适宜播种期在8月中下旬至翌年的2月中下旬。4.18份版纳黄瓜老瓜的平均β-胡萝卜素含量为106.58mg/kgDW,叶黄素0.48mg/kgDW,Vc4.96mg/100g,可溶性糖1.97%,Ca173.21mg/kg,Fe1.28mg/kg,Mg121.89mg/kg,P339.67mg/kg,Zn1.47mg/kg。不同种质的β胡萝卜素含量在1.34-261.55mg/kgDW之间。随着果实成熟期的延长,版纳黄瓜的β-胡萝卜素和α-胡萝卜素含量明显增高,叶黄素含量明显下降。在果实成熟期未检测到番茄红素。β-胡萝卜素积累是版纳黄瓜果肉颜色形成的主要原因。5.在2个组合8个果肉色相关检测指标的最优模型基本为两对主基因控制模型。浅肉色（低值）对橙黄肉色（高值）为显性。黄瓜果肉色的主基因+多基因效应决定了相关指标变异的绝大部分（90₃%～99.3%）,还有一小部分变异是由环境因素决定的。在上位性作用中,两主基因的加性×加性互作效应均较大。两组合8个检测指标在F₂主基因的遗传率较高（75.97%～99.3%）,多基因遗传率较低（0～23.66%）,以主基因遗传为主。6.构建了第一张以版纳黄瓜为构图亲本,基于黄瓜全基因组测序开发的SSR引物为标记的黄瓜分子连锁图谱。该图谱覆盖黄瓜全基因组的7条染色体,图谱总长709.9cM,相邻标记平均图距为9.59cM。7.利用黄瓜SSR分子遗传连锁框架图,在第4、第5、第6和第7染色体上分别检测到与果肉色有关的QTL8个。其中在第4染色体上检测到2个与β-胡萝卜素含量有关的主效QTL,贡献率分别达到52.8%和22.0%。另外,在第3、第4、第5和第6染色体上检测到7个QTL,分别与第一雌花节位、单瓜种子数和成株白粉病抗性有关。更多还原

【Abstract】 Xishuangbanna cucumber（Cucumis sativus L.var.xishuangbannanesis Qi et Yuan）is one variation found only in China until now.Orange flesh of mature fruit was one of the most important characteristics obviously different from common cucumbers.In this study,Morphological characterization and Simple sequence repeat（SSR） analyses were conducted to assess the genetic diversity in 30 Xishuangbanna cucumber germplasms.Two germplasms were sowed in eight months respectively in order to analyze the influence of environmental factors on sex type of Xishuangbanna cucumber.The nutrition components of 18 Xishuangbanna cucumber germplasms were analyzed during maturation.Genetic analysis of fruit flesh color of two combinations were studied using the joint analysis method of major genes plus polygene of 4 generations.SSR genetic linkage map were constructed and QTL identification were performed for important characters such as flesh color,first female node and so on.The main results are as followed.1 Identification results of 5 qualitative and 13 quantitative characters suggest that there was relatively abundant genetic diversity in Xishuangbanna cucumber at morphological level.Five quantitative characters related to sex differentiation and lateral branch development showed great difference. Based on above data,the result of cluster analysis express that 29 germplasm could be divided into 5 groups,which were basically consistent with important morphological characters.2 Relatively genetic diversity existed in Xishuangbanna cucumber population in molecular level.The percentage of polymorphic loci,Nei’s gene diversity（H） and Shannon’s information index（I） of 273 samples from 30 germplasms were 92.86%,0.1818 and 0.2972 respectively.The genetic variation among the germplasms was 54.06%and that within germplasm was 45.94%.Cluster analysis showed that the result of classification of most germplasms was consistent with major morphological characters.Among 5 populations according to accession source,the genetic diversity of Jinghong population was the highest.Cluster analyses suggest that the difference of genetic background existed in 5 populations with different collecting source.The coefficient of genetic differentiation（Gst） and gene flow（Nm） were 0.2201 and 1.7718,which indicated that the genetic differentiation was relatively low,with relatively larger gene flow in C.sativus var. xishuangbannanesis.3 The average content of 18 Xishuangbanna cucumbers were as followed:β-carotene 106.58mg/kgDW,lutein 0.48mg/kgDW,Vc4.96 mg/100g,soluble sugar 1.97%,Ca173.21mg/kg, Fe1.28mg/kg,Mg121.89mg/kg,P339.67mg/kg,Zn1.47mg/kg.It was showed that the great difference ofβ-carotene content existed among 18 Xishuangbanna cucumbers.The variation extent and variation coefficient were 1.34～261.55mg/kgDW and 67.68%respectively.With the longer maturation,the p-carotene andα-carotene content intended to be higher and that of lutein showed the adverse trend.Lycopene could not be detected during maturation The accumulation ofβ-carotene induces the orange flesh of Xishuangbanna cucumber.4 Sowed in different months,the lateral stem development of Xishuangbanna cucumber was related with their sex type differentiation.The development of female flower and lateral stem of 2 germplasms expressed opposite tendency.The plant of Xishuangbanna cucumber was sensible to low temperature and short daylight.The optimum sowing date in the protected field in Beijing was from the middle of August to the middle of February in next year.5 There were two major genes controlling fruit flesh color in cucumber.The genes controlling light flesh color（lowβ-carotene content） was dominant to that of orange flesh color（highβ-carotene content）.Most variation of relative indexes of flesh color（90.3%～99.3%） was determined by the effect of major genes plus polygenes.For F₂ generation,the heritage of major genes was high （75.97%～99.3%） and that of polygenes（0～23.66%） was low.6 A genetic linkage map based on Xishuangbanna cucumber was constructed containing 74 simple sequence repeat（SSR） markers,which covered 709.9cM of 7 chromosome of the cucumber genome, with an average distance of 9.59cM between adjacent markers.7 Composite interval mapping identified 8 QTLs related with different indexes of flesh color located on 4 chromosoms respectively.Among of them,two major QTLs ofβ-carotene content whose contribution rate were 52.8%and 22.0%respectively were identified on Chromosome 4.Seven QTLs for the characters of the first female flower,resistant to powdery mildew and the number of seeds per plant were located on chromosome 3,chromosome 4,chromosome 5 and chromosome 6 respectively.更多还原