Genetic and molecular characterisations of Tomato leaf curl virus resistance in tomato (Solanum lycopersicum L.)

Four different F-2 populations were developed involving Solanum habrochaites accession 'EC-520061' that is highly resistant to Tomato leaf curl virus (ToLCV) disease and four ToLCV-susceptible cultivars of tomato (S. lycopersicum L.), 'Punjab Chhuhara' (PBC), 'H-24', 'H-86', and 'DVRT-2'. The segregation ratios of tomato leaf curl disease development in all four F2 populations were 13:3 (resistant:susceptible), indicating a dominant inhibitory gene for leaf curl disease resistance, and 3:1 (indeterminate:determinate) indicating a single dominant gene for plant growth habit. The patterns of inheritance were shown to be additive with dominant non-allelic gene interactions for the traits of ToLCV resistance and fruit yield. Using bulk segregant analysis (BSA) and one of the F2 populations ('PBC' X 'EC-520061') above, two SSR markers (SSR218(170-145) and SSR304(158-186)) were identified for ToLCV resistance. The SSR marker SSR218(170-145) was located at 15 cM on chromosome 10, and the marker SSR304(158-186) was located at 35 cM on chromosome 7. This study will support the development of new ToLCV-resistant tomato varieties via breeding programmes.