Vol. 8, Issue 8, Part Q (2024)

Tomato leaf curl virus (ToLCV) is one of the most serious plant viral pathogens of tomatoes grown in tropical and subtropical regions of the world. The virus is a monopartite and bipartite Geminivirus, transmitted by the tobacco whitefly, Bemisia tabaci (Gennadius). Tomato cultivation, especially in autumn in north India is adversely affected due to the high incidence of tomato leaf curl virus disease and losses often exceed 90 percent. To identify the resistance source/s against this disease, 53 tomato genotypes which included Solanum pimpinellifolium accessions, selected hybrids, and their parents along with the released varieties were evaluated under natural field conditions by adapting randomized block design with two replications. The observations on disease incidence and percent disease index were recorded at different intervals and based on the disease incidence genotypes were categorized into different disease reaction groups according to which LP 9 was the only accession observed to be highly resistant. The genotypes were also tested for the biochemical basis of resistance according to which total phenols chlorophyll and SOD activity showed a positive association with ToLCV resistance whereas peroxidase and catalase showed a negative association with ToLCV and ToLCV-linked molecular markers were validated in selected genotypes.