Comparison of callus induction and somatic embryogenesis of some Iranian cottons (Gossypium Spp.) with Coker 312 and histology of somatic embryogenesis

Callus induction and somatic embryogenesis from hypocotyl explants of some Iranian cottons spp. (Hashem abad, Kerman, Termez and Sepid) were compared with Coker 312 through induction and formation of embryogenic calli on medium of Murashige and Skoog (MS) with Gamborg vitamins (B sub(5)) supplemented with the following compositions: MSB sub(1) (0.5 mg/l zeatin), MSB sub(2) (1 mg/l zeatin), MSB sub(3) (0.5 mg/l 2,4-dichlorophenoxyacetic acid, 0.1 mg/l kinetin), MSB sub(4) (1 mg/l 2,4-D, 0.5 mg/l kinetin, 0.5 mg/l zeatin) and MSB sub(5) (2 mg/l alpha -naphtalene-3-acetic acid, 1 mg/l kinetin, 0.75 mg/l MgCl sub(2)). The optimum medium for the proliferation of embryogenic calli was MS medium containing B sub(5) vitamins, 1 mg/l 2,4-D, 0.5 mg/l kinetin and 0.5 mg/l zeatin and the optimum medium for the development of somatic embryos was MS medium (NH sub(4)NO sub(3) was removed and KNO sub(3) amount doubled) containing B sub(5) vitamins, 40 g/l sucrose and without hormone. Media MSB sub(1), MSB sub(2) and MSB sub(4) gave the highest percentage (100%) of calli induction in Coker 312 but the lowest induction (46.66%) was observed when Hashem abad explants were cultured in the MSB sub(3) medium. Embryogenesis percentage of Termez (2.22 to 24.40%), Hashem abad (1.85 to 9.73%) and Sepid (9.06 to 22.28%) genotypes were significantly lower than that of Coker 312 (66.66 to 94.33%). The Kerman genotype did not show embryogenesis. In the histological studies, the different development stages of the embryos (globular, heart, torpedo and cotyledonary) together with callus cells were showed.