Effect of genotypes and culture medium on shoot regeneration and proliferation of <i>Gerbera jamesonii</i>

Abstract

Gerbera jamesonii is one of the most popular cut flowers in the world and micropropagation is the commercial way for its propagation. This method allows for obtaining large amounts of healthy homogenous plants. Thus, it is necessary to establish efficient micropropagation protocols. The objective of this study was to evaluate the organogenic response of G. jamesonii, orange and pink cultivars, under in vitro culture. Different levels of N⁶-benzyladenine (BA) (2, 4 and 6 mg/l) and thidiazuron (TDZ) (0.2, 0.4 and 0.6 mg/l) in combination with Indole-3-acetic acid (IAA) (0 and 0.1 mg/l) in MS medium were evaluated for shoot induction. For proliferation, regenerated shoots in TDZ were subcultured in medium supplemented with 0.2, 0.4 and 0.6 mg/l TDZ, 2 mg/l BA or 2 mg/l Kin and regenerated shoots in BA were subcultured on the induction medium. In the second phase, mediums of MS, ¹/₂ MS, MS with ¹/₂ NH₄NO₃ and KNO₃ concentration (MS-¹/₂N), MS with ¹/₂ micro and iron elements (MS-¹/₂MI), B₅ and ¹/₂ B₅ on shoot induction and proliferation of pink cultivar were evaluated. In order to induce rooting in the regenerated shoots, different levels of IAA (1, 2 and 3 mg/l) and 1-Naphthaleneacetic acid (NAA) (1, 2 and 3 mg/l) in combination with sucrose (30 and 40 g/l) were evaluated Maximum shoot induction, (88.8 % and 44.4 % for orange and pink cultivars, respectively) and multiplication rate (7.6 shoots/explant for orange cultivar and 1.33 shoots/explant for pink cultivar) were obtained in medium with 4 mg/l BA and 0.1 mg/l IAA. The most effective media for shoot induction and proliferation were MS-¹/₂N and MS, respectively. The best rate of shoot rooting in orange cultivar (4.6 roots/explants with 4.8 cm length) and pink cultivar (5.2 roots/explants with 6.2 cm length) was  obtained by using 3 mg/l IAA and 30 mg/l sucrose. The establishment of plantlets was done successfully with 92% of survival in the greenhouse.

Key words: Micropropagation, organogenesis, in vitro culture, Gerbera, cut flower.