Evaluation of the in vitro regeneration capacity in Brazilian industrial tomato

The objective of this work was to evaluate the regeneration capacity of the IPA-5 and IPA-6 Brazilian industrial tomato (Lycopersicon esculentum Mill) cultivars using four compositions of culture media described in the litera ture and five inoculation methods. A new variation of inoculation, the spli t cotyledon method, was also tested. The largest frequency of shoot bud for mation was 100% in the case of IPA-5 and 65% in the case of IPA-6. To induc e shoot elongation, it was necessary to accomplish three subcultures of the explants presenting shoot buds. In the case of IPA-5, the number of the ob tained shoots was higher when the induction of shoot buds was accomplished in culture medium containing BAP (2.5 mg L-1) and IAA (0.2 mg L-1) followed by three subcultures on zeatin (0.5 mg L-1) containing medium. Using such protocol, the IPA-5 cultivar produced, on the average, 5.45 elongated shoot s through the split cotyledon method. That capacity exceeded significantly the trimmed cotyledon method, which produced 4.4 elongated shoots per expla nt. In the case of IPA-6, the best combination of culture medium and inocul ation method produced 0.87 elongated shoot per explant. The elongated shoot s were rooted and transferred to greenhouse.