Effects of zeatin and activated charcoal in proliferation of shoots and direct regeneration in cotton (Gossypium hirsutum L.)

A multiple shoot induction protocol was optimized for cotton (Gossypium hirsutum L.). Three cultivars of cotton (Sahel, Siokra, Hybrid, that is, Sahel x Siokra) were used to study the effects of zeatin and activated charcoal on proliferation of shoots and direct regeneration from shoot tip explant excised from 10 - 15 day-old seedlings cultured in vitro. Growth response of different varieties varied. Root and shoot formation was observed in all varieties. The best treatment for multiple shoot induction in cultivars was the treatment containing Murashig and Skoog (MS) basal medium supplemented with zeatin (0.1 mg/l) and activated charcoal (0.5 mg/l), while treatment containing zeatin (0.1 mg/l) and activated charcoal (2 mg/l) was not good medium for regeneration. Culture of every cultivar continued for 7 subcultures and morphological characteristic was evaluated during every subculture. Maximum length of shoots (4.65 cm), the highest percentage of root development (55%) and maximum number of nodes (6.7) was observed in Siokra variety in the second subculture, Hybrid genotype and siokra in the last subculture, respectively. Also the shape of leaves changed in Siokra variety during subcultures.