Micro-propagation of Kappaphycus and Eucheuma: Trends and Prospects

Abstract

Kappaphycus and Eucheuma species have been successfully cultivated in Southeast Asia since the early 1970s. The increasing global demand for carrageenan in processed foods and thereby the need for industrial-scales of biomass to be provided to feed an extraction indus- try, exceeded wild stock availability and productivity and commercial demands could only be achieved through extensive cultivation of selected carrageenophytes. This unprecedented situation led to the introduction of carrageenophyte species and cultivars around the world; combined production of Eucheuma and Kappaphycus is one of the largest for seaweed bio- mass in the world. The activity of, and economic benefits accrued from, seaweed farming are indeed respon- sible for significant changes in rural, coastal communities in a number of important coun- tries. Such activities generating new activity and income are often the only source of cash to some of the farmers. However, in spite of the enormous size and value of the industry the techniques applied to cultivation of carrageenophytes has remained almost unchanged in the commercial farms. Seedlings (or vegetatively propagated fragments of older, larger, mature thalli) are still most commonly planted along ropes held in various configurations, in most of the major production centers, e.g. mostly classified as simple stakes in the ground (off-bottom planting to floating rafts of various design). Some technological developments have been made in Brazil and India with the implementation of tubular nets for planting, which allows a degree of mechanization on the farms; both countries are developing mechanical harvesters. Further to co-production of biomass and harvesting, the drying pro- cess is still a limiting problem for production, and drying costs are high, in countries with high rainfall, this segment of the process is discussed in detail by Ali et al. Chap. 8). Diseases such as “ice-ice” and blooms of epiphytes and endophytes (see Chap. 6 by Loureiro et al.), as well as present and impending climate change effects (see Chap. 7 by Largo et al.) are also very big challenges. In general, the production of carrageenophytes in tropical and sub-tropical regions is very dependent on the weather: as in prevailing conditions during the dry and wet seasons or surface seawater temperatures (SSTs) during “cold” winters and/or “hot” summers. For the future, efforts need to be made to increase the productivity and resistance of the selected strains