This study was conducted at the Experimental Farm of Maryout Research Station; Desert Research Center,
Alexandria Governorate, in addition to the Genetic and Cytological Laboratory of Desert Research Center, Matarya,
Cairo, Egypt; during summer growing seasons from 2012/2013 and 2013/2014, in order to evaluate some tomato
genotypes under drought stress conditions. The tolerant parent UC82B, susceptible parents, Peto82, Super Marmande and
Super Strain B with their crosses and reciprocal crosses were used. The results showed that there was unique band 35KDa
was found in hybrid UC82B×Super Strain B due to it represent specialized mechanism in the tolerant genotypes under
drought stress conditions as well as a unique band 42 KDa which was represented in hybrid Super Marmande×UC82B. In
addition, the results of peroxidaseis ozymes indicated that the unique band associated with line of UC82B. This band
could be considered as a distinguished marker for the tolerant line of UC82B under drought stress conditions. Also, the
results of polyphenoloxidase isozymes indicated that there are four common monomorphic bands were mentioned at the
bands of 1, 2, 5 and 6 with molecular weight. These common bands could consider as markers for positive identification
of previously mentioned genotypes under drought stress conditions. On the other hand, a unique band 4 associated with
line LA3772) of UC82B. This band could be considered as a distinguished marker for the tolerant line of UC82B under
drought stress conditions. Moreover, the phylogenetic tree indicated that one cluster included the hybrids Super
Marmande×UC82B and reciprocal hybrid Super Marmande×UC82B and UC82B in sup cluster as a tolerant parental
genotype.