Effect of hormones on direct shoot regeneration in tomato

This study was conducted for developing a high frequency regeneration system in two genotypes of tomato (Lycopersicon esculentum Mill.) viz., Punjab Upma and IPA-3 for direct shoot regeneration from leaf explant. The explants were excised from in vitro tomato seedlings and cultured on MS medium supplemented with different concentrations and combinations of hormones. Direct shoot regeneration was significantly influenced by the genotype, hormone combinations and concentrations. The MS medium supplemented with Kinetin (0.5 mg l⁻¹) and BAP (0.5 mg l⁻¹) was found optimum for inducing direct shoot regeneration and number of shoots per explant from leaf explants on this medium, shoot regeneration per cent in Punjab Upma and IPA-3 per cent was recorded to be highest i.e 86.89 and 76.78, respectively. Besides this, average number of shoots per explant was also highest i.e. 4.52, in case of Punjab Upma and 3.22 in case of IPA-3. A significant decline was observed in percent shoot regeneration and average number of shoots per explant with increase in the hormonal concentration. Shoots were obtained and transferred to the elongation medium (MS + BAP 0.3 mg l⁻¹). Hundred per cent rooting was induced in separated shoots upon culturing on MS and ½ MS basal media. Hardening on moist cotton showed maximum plantlet survival rate in both genotypes. After hardening, plants were transferred to soil. Thus, a tissue culture base line was established in tomato for obtaining direct regeneration using leaf as explant.