Somatic embryogenesis and plant regeneration of recalcitrant cottons (Gossypium hirsutum)

Many restrictive factors still remain in cotton tissue culture such as long duration, unpredictability and a high degree of genotype dependence. The main objective of this study was to develop a protocol allowing consistent somatic embryogenesis and plant regeneration from five recalcitrant cotton cultivars. Our results showed that the best medium for calli induction is MSB (MS medium + vitamine B5) supplemented with indolebutyric acid (IBA, 0.1 mg.l-1), kinetin (KIN, 0.1 mg.l-1) and 2,4- dichlorophenoxyacetic acid (2,4-D, 0.1 mg.l-1). Embryogenic calli of all the five genotypes used were successfully from MSB medium supplemented with IBA (0.3 mg.l-1) and KIN (0.05 mg.l-1). Somatic embryos and transformation of somatic embryos into plants were successfully induced on MSB medium supplemented with ×NH4NO3 (825 mg.l-1), 2×KNO3 (3800 mg.l-1), glutamine (2.0 g/l) and asparagines (0.5 g/l). The protocol developed in this study for cotton plant regeneration could be shortened to 4 - 5 months. Furthermore, the firstly-obtained regenerated plants of above five cultivars will broaden the range of genotypes for in vitro manipulation for cotton improvement.