中文摘要：

【目的】蔓枯病（gummy stem blight）是一种真菌性土传病害,是危害甜瓜生产的严重病害之一,其存在生理小种的分化,品种即使仅携带单个抗病基因,仍会导致甜瓜抗性逐步降低甚至丢失。建立甜瓜抗蔓枯病聚合育种的分子标记辅助选择体系,选育抗性高且不再分离的聚合抗源自交系和品质优良且高抗甜瓜蔓枯病的改良白皮脆品种（品系）,为甜瓜优质、抗病和高产育种提供一种简单、快捷的选择方法和重要的中间材料。【方法】利用5份甜瓜单一抗源材料PI140471、PI157082、PI511890、PI482398和PI420145两两杂交获得8份聚合抗源（082-471、082-890、082-398、145-471、145-082、145-890、145-398和890-398）。利用3个不同浓度的蔓枯病病菌孢子液（5×105个/m L、5×107个/m L、5×109个/m L）对8份聚合抗源的F1植株幼苗进行接种鉴定。结合春、秋两季的接种鉴定结果,筛选得到2份聚合后抗性显著提高的基因组合145-471和145-398。一方面,以145-471和145-398为材料,利用苗期梯度接种鉴定、分子标记辅助选择以及农艺性状观察,对其自交后代进行逐代筛选至F7。另一方面,选用组合PI420145和PI140471以及PI420145和PI482398作为蔓枯病抗性基因的供体亲本,综合性状优良的感病甜瓜品种‘白皮脆’为抗性基因受体亲本。先分别单向回交5代,在单个基因回交转移时,利用分子标记检测结合农艺性状观察对回交后代进行筛选。当回交后代的遗传背景得到一定程度恢复后,再将2个方向的回交后代进行杂交,后自交3代稳定。【结果】聚合抗源对不同浓度的蔓枯病菌均表现为抗,而单一抗源对不同浓度蔓枯病菌表现出选择性抗性且抗性水平低于聚合抗源。SSR标记CMCT505和CMTA170a在PI140471和PI482398上可分别扩增出189 bp和121 bp的特异性片段,SCAR标记SGSB1800可以在PI420145上扩增出1 800 bp的特异性片段,而145-471（145-398）的聚合?

英文摘要：

【Objective】Gummy stem blight（GSB） is caused by Didymella bryoniae and is a serious fungal disease of melon（Cucumis melon L.）. The resistance of melon varieties carrying a single resistance gene is not enough to the disease because of the isolates variation of Didymella bryoniae. Therefore, this study aims to develop a molecular marker-assisted selection system and provide an important intermediate materials for melon disease-resistance breeding. 【Method】Firstly, the single resistant sources PI140471, PI157082, PI511890, PI482398 and PI420145 were used to obtain polymerization resistant sources（082-471, 082-890, 082-398, 145-471, 145-082, 145-890, 145-398 and 890-398）. Secondly, three different gradient spores vaccination identification（5×105 spores/m L, 5×107 spores/m L and 5×109 spores/m L） was employed to distinguish the resistance of F1 plant of eight different polymerization resistant sources. The gene combinations of 145-471 and 145-398 with their resistance significantly improved were screened by inoculation identification results of spring and autumn. Single resistant sources PI140471, PI482398 and PI420145 were used as the donor parents with the gummy stem blight resistance genes Gsb-1 Gsb-4 and Gsb-6, respectively. Commercial melon cultivar Baipicui was used as the receipt parent to cross and backcross with the donor parents. Marker assisted selection（MAS） and gradient spores vaccination identification（5×105 spores/m L, 5×107 spores/m L and 5×109 spores/m L） were used in each backcross and self-cross progeny. 【Result】The single resistant sources showed lower resistance than polymerization individuals and showed selective resistance to the different gummy stem blight spore concentrations（5×105 spores/m L, 5×107 spores/m L and 5×109spores/m L）. The detection results of molecular markers showed that all the individuals of 145-471（or 145-398） F7 and BC5F4 generation had two resistance genes of Gsb-1 and Gsb-6（or Gsb-4 and Gsb-6）. The polymorphism of mo