Tomato (Solanum lycopersicum L.) is an important economic crop worldwide. In Mauritius, three types of tomatoes are grown: cooking, salad and cherry tomatoes. The salad and cherry tomatoes are grown under hydroponic systems whereas the most widely consumed tomato, the cooking type, is cultivated in open fields and thus is subject to adverse climatic conditions. Tomato with increased tolerance to abiotic stresses, especially heat, is essential for the small island economy. To address this, a mutant population of cooking tomato was developed using gamma irradiation. Two advanced mutant lines were identified exhibiting increased tolerance to heat stress. These mutant lines also showed an early flowering phenotype, with different fruit shape and plant architecture compared to the parental line. Whole genome (re)sequencing was applied at the M7 stage to identify sequence variations between the two mutant lines and their parent. Our data shows differences in the frequency and spectrum of sequence variants in the two mutant lines. In L25P10, 175,116 unique SNPs were detected, whereas in L5P12, 49,690 SNPs could be detected. Likewise, differences were observed in the case of small InDel with 42,435 and 12,370 detected in L25P10 and L5P12 respectively. Variants can produce effects of different types and affecting different regions of the genome. Less than 1% of SNPs and InDels identified in both mutants are predicted with high impact of the effect. Similar differences were noted in the number of Structural Variants identified in both mutants with L25P10 showing twice more Deletions, Inversions and Duplications. We are currently conducting in silico analysis to identify candidate causative mutations for the observed traits.