Objective The frequent occurrence of diseases in tomato production has seriously affected the yield and quality of tomato. Molecular maker technology was used to detect 9 resistance genes of 6 serious diseases in tomato, in an attempt to discover multi-resistant germplasm resources so as to provide theoretical basis for tomato resistance gene pyramiding.

Method Tomato total DNA was extracted by CTAB method, and the gray leaf spot resistance gene Sm, leaf mold resistance genes Cf-5 and Cf-9, tomato yellow curl virus disease resistance genes Ty-1, Ty-2 and Ty-3/3a, root-knot nematode disease resistance gene Mi, fusarium wilt resistance gene I-2 and late blight resistance gene Ph-3 of 200 tomato materials were amplified by PCR according to the published primers.

Result Among 200 tomato materials, 90 materials contained homozygous resistance gene Sm, and 19 were heterozygous; among leaf mold resistance genes, Cf-5 was found in 12 materials, and Cf-9 was found in 162 materials; among tomato yellow leaf curl virus resistance genes, 33 materials contained homozygous Ty-1 and 17 were heterozygous, 7 materials contained homozygous Ty-2 and 1 was heterozygous, 31 materials contained homozygous Ty-3/3a and 20 were heterozygous; for root-knot nematode resistance gene Mi, 60 materials were homozygous and 28 were heterozygous; for fusarium wilt resistance gene, 75 materials contained I-2; among the late blight resistance gene Ph-3, 25 materials were homozygous and 5 were heterozygous. Among these tomato materials, there were 126 materials containing three or more resistance genes, accounting for 63% of the total, including 19 contained 5 genes, 4 contained 6 genes (line L36-1, Q9-1, Q9-2 and TianF4). None of the materials had 7 or more resistance genes.

Conclusion Among the 200 tomato materials, 126 contains 3 or more resistance genes, indicating that this batch of tomatoes have good potential for application, especially the materials L36-1, Q9-1, Q9-2 and TianF4, all contain 6 resistance genes, which could be used as candidate multi-resistance germplasm resources for further screening and identification.