Abstract

Induction of multiple shoots of cotton (Gossypium hirsutum L.) plant in two commercial varieties (Sahel and Varamin) using shoot apex was done. Explants were isolated from 3 - 4 days old seedlings, then they were cultured on a shoot induction media, modified MS nutrient agar with combinations: 1- Kinetin (0.0, 0.5, 1.0, 1.5 mg l^-1) and 6-benzyaminopurine (BAP) (0.0, 0.1, 0.5, 1.0, 1.5 mg l^-1), 2- α-naphthaleneacetic acid (NAA) (0.0, 0.1, 1.0 mg l^-1) and BAP (0.0, 0.1, 0.5, 1.0, 1.5mg l^-1). After 1.5 - 2 months, multiple shoot induction medium with 0.1 mg l^-1 NAA and 0.1 mg l^-1 BAP resulted in the highest number of regenerated shoots per explant (3 - 4 shoots per explant) for the two cultivars. Elongation of multiple shoots was obtained on modified MS nutrient agar without any phytohormone. In vitroshoots were rooted on half-strength agar-solidified MS basal medium supplied with 0.1 mg l^-1 Iidole-3-butyric acid (IBA) and MS vitamins.

Key words: Cotton, Shoot apex, multiple shoot.