Assessment of genetic diversity within eucheumatoid cultivars in east Sabah, Malaysia

Studies have shown that cultivars of the carrageenophytes <i>Kappaphycus</i> and <i>Eucheuma</i> are clones of a limited number of strains originally domesticated from wild populations. For the development and selection of new cultivars, it is important that a comprehensive record of available variants exists. This study was conducted to provide up-to-date analysis and compilation of the current state of cultivars as the last list of cultivars was compiled nearly a decade ago. The present study analyzed the <i>cox</i>2–3 spacer and <i>cox</i>1 (1356 bp) genetic diversity of cultivars collected from 2019 to 2020 from the east coast of Sabah where the seaweed farms are concentrated. These data were compared with cultivars reported from 2010 to 2012 to assess changes, if any, to the gene pool of farmed eucheumatoid in Malaysia. <i>Kappaphycus alvarezii</i>, <i>K. striatus</i>, and <i>K. malesianus</i> are currently cultivated while <i>Eucheuma denticulatum</i> is no longer an important cultivar compared to a decade ago, probably due to its lower price. Analysis of the <i>cox</i>2–3 spacer revealed a new haplotype, LBT10, and, by including published GenBank data, a further four previously unnamed haplotypes were recognized from Sabah. This study confirms that there is a limited gene pool within cultivars in Malaysia and suggests the need for new or genetically diverse cultivars which can adapt to a changing environment, to ensure a more sustainable carrageenan industry.