Abstract: There are diverse origins of cultivated Sargassum fusiforme (Harv.) Setch. in Dongtou, Zhejiang Province. In this paper, 5 strains of S. fusiforme were investigated, of which one came from Korea, three were collected from Dongtou, Nanji Island, Dongji Island of Zhejiang Province, and the last one was from Shantou, Guangdong Province. Significant differences were found among the five strains in the algal weight and height. The strain of S. fusiforme from Korea had better growth advantages than others, so it could be used as target strain for breeding. The genetic diversity of S. fusiforme was analyzed by ISSR makers. The genetic distances among the samples were calculated by Popgen 32 and the cluster analysis was performed by UPGMA method. The results showed that 11 ISSR primers could amplify polymorphic and informative bands from the 36 screened primers. Total 219 DNA bands were amplified, of which 129 were polymorphic and the percentage of polymorphic loci reached to 58.9%. The genetic distances of the 5 samples varied from 0.151 0 to 0.382 4. In the dendrogram, five strains of S. fusiforme clustered into one clade and S. thunbergii were in the outgroup. The study revealed that the genetic diversity of the cultivated S. fusiforme in Dongtou was low on the DNA molecular level, which provided theoretical reference for the developing genetic resources conservation and superior seed breeding of S. fusiforme in the future.

Key words: Sargassum fusiforme (Harv.) Setch., cultivated characteristics, ISSR, genetic diversity