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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).

The South-Western highlands of Ethiopia are considered to be the centre of origin and diversity of the arabica coffee, Coffea arabica. More than 80 accessions of arabica coffee collected from Ethiopia are available in Indian gene bank. However, the genetic diversity of these accessions is not studied in detail. In the present study, genetic diversity analysis of 48 accessions collected from eight provinces of Ethiopia was carried out using Sequence-related amplified Polymorphism (SRAP) marker. Among the thirty two SRAP primer combinations tested, 14 primer pairs were polymorphic and generated 203 distinct fragments. The number of fragments ranged from 7 to 21 with a mean of 14.5 fragments per primer combination. Of the total 203 amplified fragments, 182 (89.65%) were polymorphic and the percent of polymorphism ranged from 53.84% to a maximum of 100% using different primers. The average resolving power (Rp) and average polymorphism information content (PIC) of the 14 SRAP primer combinations was 14.31 and 0.648 respectively. A total of 13 rare alleles were obtained from SRAP assays, of which six rare alleles were obtained from the accessions collected from Shoa province. The UPGMA clustering algorithm from SRAP analysis grouped the 48 coffee accessions into two major clusters. The accessions collected from particular province clustered together which could be attributed to the substantial gene flow between adjacent population and the influence of geographical origin on genetic diversity. The study demonstrated the existence of substantial genetic variation in Ethiopian germplasm which could be utilized in coffee germplasm conservation and improvement program.

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