Somatic embryogenesis from integument (perisperm) cultures of coffee.

Somatic embryogenesis was induced in integument (perisperm) cultures of C x R hybrid cultivar of coffee, after a culture period of 15 months, using a sequence of 3 modifications of MS medium. Vigorously growing soft, white, watery crystalline calli were obtained on MS + TIBA (1 mg/l) + L-cysteine HCl (50 mg/l) + PVP (100 mg/l). After 45 d, the calli were subcultured to MS + IAA (0.5 mg/l) + 2,4-D (0.05 mg/l) + Kn (8.6 mg/l) and maintained for the next 9 months without any transfer. On this medium, the callus proliferation was initially vigorous which slowed down after 5-6 months, and then the calli turned light brown and somewhat compact. Later, when the calli were transferred to MS + thiamine HCl (10 mg/l) + pyridoxine HCl (3 mg/l) + nicotinic acid (2 mg/l) + 2,4-D (0.2 mg/l) + 2ip (2.5 mg/l) and cultured for 2 months, they turned darker, more compact and the proliferation almost stopped. These calli were subcultured onto fresh medium of the same composition. After another 2 months of culture cream-coloured, highly friable, embryogenic calli appeared, which in turn produced a few clearly identifiable SEs in another 1 month. Further proliferation and maturation of SEs was achieved by culturing the embryogenic calli on MS + ABA (1 mg/l) for 3 months. The SEs were germinated into 2 cm tall plantlets after 2-3 subcultures, each of 2 months duration on 1/2-MS + Kn (0.1 mg/l).