Effect of Genotype and Explant Type on in Vitro Shoot Regeneration of Tomato (lycopersicon Esculentum Mill.)

In order to select the best tomato cultivar for Agrobacterium mediated gene transformation studies, In vitro regeneration frequency of hypocotyls, leaf disc and shoot tip of five tomato cultivars (Lycopersicon esculentum) was investigated on a regeneration medium supplemented with 1 mg/l zeatin and 0.1 mg/l indole-3-acetic acid. Significant differences in regeneration capacity between genotypes and explant types, expressed as frequency of regeneration, average number of callus, shoot primordial and regenerated shoot primordial were observed. Regeneration in 5 cultivars of tomato using 3 different explant types was achieved. The regeneration capacity was strongly influenced by the cultivar and explant type. The highest regeneration capacity was observed in cultivar Riograndea (80% by using shoot tip, 64.5% by using hypocotyl and 56% by using leaf disc) from all types of explant. Of the explant types shoot tip was found the best explant source for direct shoot formation (80% shoot primordial were regenerated) while hypocotyl was found the best explant source for shoot formation through callogenesis (64.5% shoot primordia were regenerated)