Deciphering gene specific molecular characterization and partial gene sequence for combined resistance to tomato leaf curl virus (ToLCV) (Ty-1, Ty-2 and Ty-3), fusarium wilt (I-2) and root- knot nematode (Mi-1) in selected fresh market breeding line of tomato (Solanum lycopersicom L.).

Background: Tomato (Solanum lycopersicum L.) is a widely cultivated crop in tropical regions, but its production is often hampered by significant losses attributed to diseases like tomato leaf curl virus (ToLCV), fusarium wilt and root-knot nematode.

Methods And Results: This study employed an integrated approach utilizing both co-dominant and dominant SCAR markers, selected for specific resistance genes (ToLCV-Ty-1, Ty-2, Ty-2, Fusarium wilt (Race-2)-I-2, and Root-knot nematode-Mi-1. These markers with their specific gene of interest were used to screen the ten fresh market breeding lines of tomato. The P625 marker played a pivotal role in the identification process of Ty-3 alleles and effectively distinguishing between Ty-3a and Ty-3. I-2/5 (Fusarium wilt I-2), and Mi-23 (Root-knot nematode Mi-1) effectively identified and discriminated between heterozygous and homozygous states of specific genes. All resistant lines and a susceptible line for ToLCV (Ty-1, Ty-2, Ty-3), Fusarium wilt ((Race-2)- I-2) and Root-knot nematode underwent sequencing using specific primer pairs through the Sanger dideoxy technique. The resulting nucleotide sequences were aligned utilizing MEGA7 bioinformatic software and subjected to nucleotide BLAST in the NCBI database to determine sequence per cent identity and query cover, facilitating comparison with other submitted sequences.

Conclusion: The determination of genomic positions for these nucleotide sequences may enable researchers to cartographically pinpoint the locations of genetic variations within the genome.