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。

Genetic variability in modern crops is limited due to domestication and breeding. To investigate genetic variation in different populations, 216 tomato (Solanum lycopersicum L.) cultivars, hybrids, and elite breeding lines from four breeding programs were genotyped using single nucleotide polymorphism and simple sequence repeat markers. Of 47 markers analyzed, 72.3% were polymorphic in the whole collection of 216 genotypes and 51.06 59.57% showed polymorphisms in individual populations. However, genetic variation was narrow in all four populations, Nei's genetic distance varied from 0.0422 to 0.1135 between populations and from 0.0085 to 0.3187 between lines in individual populations. Cluster and principal coordinate analysis indicated that the four populations could be grouped into three clades. Lines from Shenyang Agricultural University and China Agricultural University population formed the first clade, lines from Beijing Vegetable Research Center were in the second clade, and lines from Nunhems were in the third clade. This was further supported by population structure analysis using STRUCTURE2.2, and suggested that a lack of germplasm exchange might exist among breeding programs. It rnight be the reason that the progress of developing new varieties with significant improvement of horticultural traits in China is slow in recent years.

试验采用聚乙二醇（PEG）6000溶液模拟水分胁迫条件（0、-0.2、-0.4、-0.6、-0.8 MPa）对包括3份醋栗番茄、4份栽培番茄的变种和2份对照的种子进行萌发试验，结果显示，在-0.4、-0.6、-1.8 MPa水势下，所有材料都不能发芽。在-0.2 MPa水势下，供试材料的发芽能力都比正常水分（0 MPa）下有所下降，且材料间差异显著，NC 84173和LA 4133发芽最差，而PI114490表现最好，可作为耐旱材料用于育种。

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.