Variability in indigenous Pakistani tomato lines and worldwide reference collection for Tomato Mosaic Virus (ToMV) and Tomato Yellow Leaf Curl Virus (TYLCV) infection.

Local and exotic germplasm of tomato remains a major source for genetic improvement. Assessment of such lines for biotic stresses particularly viral diseases are the most important criteria for selection in Pakistan, where Tomato Yellow Leaf Curl Virus (TYLCV) and Tomato Mosaic Virus (ToMV) are the major diseases/viruses. A set of 40 accessions (including indigenous Pakistani lines and exotic germplasm from Europe, the United States, and Asia) were evaluated for their resistance/infection response to ToMV with artificial inoculation under greenhouse conditions. Infection response was quantified through disease scoring and DAS-ELISA test (for ToMV). A subset of 24 lines, was further screened for TYLCV using disease scoring and TAS-ELISA. The tested lines showed significant variability for resistance to ToMV. Only one accession (Acc-17878) was resistant to the ToMV whereas seven accessions i.e. Acc-17890, AVR-261, CLN-312, AVR-321, EUR-333, CLN-352, and CLN-362 expressed resistance to TYLCV. Correlation between phenotypic evaluation was confirmed by the ELISA results in both diseases, although both tools complemented to assess the viral infection status. In future, tomato breeding programs must consider breeding for ToMV and TYLCV resistance (using identified germplasm in our study) so as to deliver virus resistant tomato varieties.