Identification and validation of an ISSR marker linked to Tomato leaf curl New Delhi virus resistant gene in a core set of tomato accessions

Tomato leaf curl disease causes yield loss in tomato all over the world. Despite of various efforts no immune commercial varieties or F₁ hybrids are available in India. Tomato yellow leaf curl virus resistance linked genes have been identified and introgressed from several wild tomato species. Here, we aimed to identify PCRbased markers linked to gene(s) confering resistance to Tomato leaf curl New Delhi virus (ToLCNDV). This study covers the generation of a BC₁F₁ population derived from a reciprocal cross between a ToLCNDV tolerant accession of Solanum habrochaites LA1777 and susceptible cultivar 15SBSB (Solanum lycopersicum L.). Genetic analysis of 135 plants of BC₁F₁ population indicated that three dominant genes confer resistance to ToLCNDV in the accession S. habrochaites LA1777. Using Bulk-Segregant-Analysis, we identified an ISSR marker, which produced a 564 bp fragment in the tolerant wild accession and also in the tolerant bulk sample. The identified marker has been validated in a set of 18 diverse tomato accessions and can be used as a diagnostic marker to assist marker-assisted-breeding for ToLCNDV tolerance in tomato.