The research work was conducted to understand the morphological and physiological mechanisms of salt tolerance in tomato. The genotypic responses of 72 tomato genotypes to salinity have been compared using absolute and relative values measuring shoot and root lengths, and their fresh weights. As the relative/absolute root length had the highest heritability among all the four traits therefore it was used to select salt tolerant (LA2661, CLN2498A, CLN1621L, BL1176, 6233 17870) and non-tolerant genotypes (17902, LO2875 and LO4360). The differing salt tolerance of these genotypes was also verified by analysing Na+, K+ contents and K+/ Na+ ratio. The tolerant and non-tolerant genotypes were grown to maturity to see whether or not the selected genotypes maintained their degree of salt tolerance. The data of F1 hybrids between six tolerant and three non-tolerant parents under normal and saline conditions were collected and analysed to determine the gene action involved in the expression of these characters. The estimates of GCA, SCA and heterosis were also made for various morpho-physiological characters to select the combinations better than parents.