Achievement of higher production and productivity in any crop, good quality seed is one of the essential requirements in production and supply. Seeds undergo deterioration resulting in a decline in germination and vigour during storage. It is essential to keep the quality of seed during storage. With this view, the present investigation had been undertaken to determine the trends in seed deterioration of tomato was observed by storing with six treatments in seed testing laboratory after harvesting from field in 2020-2021 at Seed Testing Laboratory, Department of Seed Science and Technology, BCKV, Mohanpur, Nadia, West Bengal, India. Seeds were harvested from control plot for each replication. Then the properly dried seeds of tomato were primed with marigold petal extract @ 0.75% (T₁); Neem leaf powder @ 75g kg^-1 seed (T₂); Thiram @ 2g kg^-1 + Imidachloprid @ 7.5ml kg^-1 (T₃); Thiram @ 2g kg^-1 + Polymer @ 7ml (T₄) and Bromocresol solution @ 0.75% (T₅). Control (without treated) dry seeds were considered as T₀. Treated seeds were dried properly and maintain at 6% seed moisture content. Then the seeds were kept in 700 gauge polythene packet. Different physiological and biochemical parameters were recorded just after harvesting as well as at every two months interval up to ten months of storage. Among the different seed treatments, T₃ (Thiram + Imidachloprid) was the best as germination percentage, vigour index, soluble protein content of seeds, total carbohydrate content recorded highest and lowest value of electrical conductivity was recorded in T₃ (Thiram + Imidachloprid) when average over durations. The interaction between treatments and durations, a change in germination behaviour was found to be noticed in seed treatments from second months after storage onwards, which showed that from second months after storage onwards T₃ (Thiram + Imidachloprid ) recorded maximum potential of germination and vigour at every two months interval upto ten months of storage. But at ten months after storage germination percentage dropped below Indian Minimum Seed Certification Standard for each seed treatment including control, though it dropped below 70% for control at eight months after storage. Protein and carbohydrate content remained always highest or second highest; electrical conductivity was lowest throughout the different storage periods when the seeds were treated with T₃ (Thiram + Imidachloprid).