BAR TODAY || Official Quarterly Publication of the Bureau of Agricultural Research

Archives (2003) : Fisheries

Diversity of Eucheuma and Kappaphycus seaweeds
by Thea Kristina Pabuayon

January-March 2003
Volume 5 No. 1

The Philippine seaweed industry has come a long way since its first export venture in the 70s, and today, is one of the world's leader in the production of carrageenan-producing seaweeds.

E. denticulatum

K. alvarezzi (brown)

K. alvarezzi (green)

Carrageenan is an important powder derived from processed seaweeds and is used as enhancer, binder, thickener, and fat, foam and emulsion stabilizer in milk water food products, cosmetics, pharmaceuticals, and other non-food products.

In the Philippines, the seaweed industry is successful due to the large-scale cultivation of K. alvarezii, a kappa-carrageenan-producing species, and E. enticulatum, an iota-carrageenan-producing species. According to the Bureau of Fisheries and Aquatic Resources, these species are the most economically important seaweeds in the country, and ranks third among fishery products in export returns.

Although these seaweeds are very important commodities, little is known about their genetic diversity. With the support of DOST, PCAMRD, and UNDP, Dr. Arturo O. Lluisma of the Marine Science Institute in UP Diliman headed a team of scientists to investigate the different Kappaphycus and Eucheuma cultivars found in the Philippines and compare their commercially important characteristics such as growth rates, yield and quality. His study won an AFMA Best R&D Paper Award in the 14th National Research Symposium organized by the Bureau of Agricultural Research in 2002.

According to Lluisma, the industry can fully utilize and conserve these seaweeds if their cultivar-specific characteristics are known. "Accurate identification is needed in the carrageenan industry as some commercially important characteristics, like carrageenan yield and quality, may be species- or even strain-specific," Lluisma explained. "Our findings expand the known genetic base that can be exploited for
improving these seaweed crops," he adds.

The seaweed investigation
Dr. Lluisma and his team collected 11 cultivars of K. alvarezii and three cultivars of . denticulatum from farming areas in northern, central and southern Philippines. To investigate the genetic diversity of the two seaweeds, the team used Random Amplified Polymorphic DNA (RAPD) technique--a tool developed for the analysis of genetic fingerprints--for all 14 cultivars, and sequence analysis of the rbcL gene and rbc spacer for selected K. alvarezii cultivars.

Based on morphological and molecular analyses, the scientists found that the K. alvarezii cultivars were more genetically diverse than E. denticulatum, as revealed by the high polymorphism of the RAPD fingerprints. However, the three K. alvarezii cultivars also had low sequence divergence in both rbcL and rbc spacer regions, consistent with findings of previous research on other red algae. According to the scientists, the rbcL and rbc spacer sequences among the K. alvarezii cultivars were "highly conserved". "The sequences formed a tight group in phylogenetic trees, indicating that the Kappaphycus cultivars are closely related and quite distinct from Eucheuma species," Lluisma explained.

Based on morphological and molecular data, "Sacol", a fast-growing variety of K. alvarezii, emerged as the most divergent, though still closely related to the other Kappaphycus cultivars. The scientists pointed out, however, that since their cultivars were collected from three sites only, it is likely that their study revealed only a fraction of the actual diversity of the country's Kappaphycus and Eucheuma genetic resources. According to them, "the extent of diversity of the cultivars used by farmers in the different regions of the country remains to be evaluated."

In this regard, the scientists recommended further studies. They believe that a full inventory of these genetic resources will not only make possible the optimal use of these resources but perhaps more importantly, ensure their conservation as well.

Source: Genetic diversity of Kappaphycus and Eucheuma cultivars in the Philippines by Arturo O. Lluisma, et al. For more information, contact Dr. Lluisma at Tel. no. 922-3959 or 9205301 local 7427, or email him at aol@upmsi.ph.