The lack of resistance to bacterial diseases increases both the fi nancial cost and environmental impact of tomato (Lycopersicon esculentum Mill.) production while reducing yield and quality. Because several bacterial diseases can be present in the same fi eld, developing varieties with resistance to multiple diseases is a desirable goal. Bacterial spot (caused by four Xanthomonas Dowson species) and bacterial speck (caused by Pseudomonas syringae pv. tomato Young, Dye and Wilkie) are two economically important diseases of tomato with a worldwide distribution. The resis-tance gene Pto confers a hypersensitive response (HR) to race 0 strains of the bacterial speck pathogen. The locus Rx3 explains up to 41% of the variation for resistance to bacterial spot race T1 in fi eld trials, and is associated with HR following infi ltration. Both Pto and Rx3 are linked in repulsion phase on chromosome 5. We made a cross between two elite breeding lines, Ohio 981205 carrying Pto and Ohio 9834 carrying Rx3, to develop an F2 population and subsequent inbred generations. Marker-assisted selection (MAS) was applied to the F2 progeny and to F2:3 families in order to select for coupling-phase resistance. Thirteen homozygous progeny from 419 F2 plants and 20 homozygous families from 3716 F3 plants were obtained. Resistance was confi rmed in all selected families based on HR in greenhouse screens using bacterial speck race 0 and bacterial spot race T1 isolates. Resistance to bacterial spot race T1 was confi rmed in the fi eld for 33 of the selected families. All selected families were also resistant to bacterial speck in the fi eld. MAS was an effi cient tool to select for desirable recombination events and pyramid resistance.

为了明确我国主栽品种对番茄疮痂病抗性状况，本研究以我国番茄疮痂病主要小种T1和T3的菌株接种我国目前种植的39个番茄品种，并通过分子标记进行分析和辅助育种。结果表明，虽然有些品种具有了抗性材料的特征条带，但所有材料对T1和T3小种都不能产生过敏反应。采用与T1小种抗性位点脚紧密连锁的分子标记，成功地将抗病品种OH9834的抗性位点Rx3转移到9个不同的感病品种中，获得了抗病植株。从本研究可以看出，我国番茄品种缺乏对番茄疮痂病的抗性，同时也表明分子标记辅助选择可以用于番茄疮痂病的抗性育种中。

分子标记辅助选择为选育由多基因控制的或易受环境影响的性状提供了一条有效的途径。番茄分子标记的开发工作已经进行了三十多年，到目前为止已有2300多个不同类型的分子标记被开发和定位到12条染色体上。很多文献对这些分子标记的特点及其在番茄遗传育种中的应用进行了综述，但对其开发过程却很少提及。因此本文就主要类型的番茄分子标记的开发进展进行概括并分析其开发前景。