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The morphogenetic potential of shoot tip explants of black pepper (Piper nigrum) was investigated and an effective multiple-shoot propagation method is described. Various combinations of media, growth regulators and sterilization treatments were compared. Problems with establishment in tissue culture sometimes occurred, probably caused by endogenous pathogens associated with tissue exudates. The best establishment and proliferation of shoot tip explants was obtained on MS medium containing 1.5 mg l(-1) BAP alone; subsequent growth and development of lateral branches was best on media containing 1.5 mg l(-1) BAP plus 3.0 mg l(-1) IBA. Adenine sulphate inhibited the number of explants showing regeneration but increased the number of shoot buds per regenerating explant. Shoots were rooted on a 50% strength medium containing 1mg l(-1) NAA.

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Embryogenic callus derived from zygotic embryos of black pepper (Piper nigrum Linn.) were induced to form somatic embryos on solid and liquid Schenk and Hildebrandt basal medium. Callus proliferation, somatic embryogenesis and germination of embryos were achieved in about 8 months in static cultures while it took only 8 weeks in liquid suspension cultures. The highest number of embryos and plantlets was produced from cells grown as suspension cultures raised in half-strength medium without growth regulators and sucrose level reduced from 3% to 1.5%. Regenerated plants were established in soil.Abbreviations: 2,4-D -2,4-dichlorophenoxy acetic acid; SH -Schenk and Hildebrandt Black pepper is one of the most widely used spices in culinary preparations, food processing, perfumery and as a condiment. A major constraint in cultivation of the crop is its low productivity due to poor genetic stock and incidence of pests and diseases. All the 64 cultivats of Piper nigrum identified in India produce seeds.However, seed propagation in the species is cumbersome, uncertain and yields only a few heterogeneous progenies due to their short viability and high sterility in post-fertilization stages (Kanta, 1962). Black pepper is, therefore, conventionally propagated through cuttings with 2-6 nodes for nursery and field plantations. Plantlets have also been obtained from micropropagated shoot tips of mature vines (Philip et al., 1992) and seedlings (Mathews and Rao, 1984). However, to our knowledge, black pepper plants have not been raised from somatic embryos. Callus-mediated somatic embryos with dependable growth characteristics and plant regeneration are beneficial for raising improved varieties through in vitro selection from high-yielding callus lines and possibly also for genetic transformation. The present study reports an effective protocol for whole plant regeneration from somatic embryos of black pepper in static and suspension cultures.Ripe seeds of Piper nigrum Linn. C.V. Karimunda and Panniyur-1 were collected from plants grown in the Botanical gardens at the University of Calicut. The outer fleshy mesocarp was washed off under slow running water before being surface sterilized with 0.1% mercuric chloride for 5 minutes followed by three rinses with sterile distilled water for 5 min each. The embryo within the seed was dissected out aseptically with a sterile scalpel. The dissected embryos were incubated singly on filter paper bridges in 60 ml culture tubes containing 15 ml liquid SH (Schenk and Hildebrandt, 1972) medium, 20% without and 80% with 2,4-D (0.5-5 mg 1-1 ). The pH of the medium was adjusted to 5.7 prior to autaclaving. The cultures were maintained in dark at 24 -4-2°C with subculture carried out bimonthly to full-strength or half-strength SH medium without growth regulators. Suspension cultures were initiated by transferring 5 mg callus into 100 ml Erlenmeyer flasks containing 25 ml full or half-strength medium. The flasks were wrapped in with black paper and cultures were maintained at 110 rpm on a g...