Genetic Analyses Of Five Populations Of Laminaria Japonica Inferred From AFLP

Laminaria japonica is one of the most important economic algae which used as food and as raw materials for algin,mannitol,and iodine extraction. The commercial cultivation of seaweed began in 1950s. After half a century of development,in 2008, the culturing area of Laminaria has reached 33 thousands hectares,yielding more than 0.80 million tons of air-dried Laminaria japonica. China is the biggest country in scale of breeding and yielding.Although the AFLP technique in the study of Laminaria japonica have been some reports, however, as the size and extent of higher plants,there is a big gap. Other molecular markers researched for Laminaria japonica in the slow progress. For example,the number of SSR markers is still so small,can not satisfy the genetic analysis of complex genome of Laminaria japonica. Through this study, we want to research the application of AFLP and established method of AFLP on Laminaria japonica in further. In addition, this study expect to use AFLP for exploration of the genetic diversity and genetic relationship of major five cultivars, to its identification and assessment of seed breeding.The genetic diversity and relationships of five representative cultivars of Laminaria japonica were investigated using amplified fragment length polymorphism (AFLP) markers. A total of 197 bands were generated across all samples by 11 primer combinations. At the cultivar level, the percentage of polymorphic loci (P), gene diversity (H) and Shannon's information index (I) was highest in the Sanhai cultivar (P:38.58%;H:0.1580;I:0.2291) and lowest in the Lianza No.2 cultivar (P:25.89%;H:0.1056;I:0.1530). At the species level, P, H, and I was P:38.58%;H:0.1580;I:0.2291 respectively. A UPGMA dendrogram were constructed based on the Dice similarity coefficients among individuals and genetic distances among cultivars. Analysis of molecular variance (AMOVA) revealed that 45.53% of variations resided among cultivars, while 54.47% within cultivars. The GST value was 0.3917, and the gene flow (Nm) was 0.3882, indicating moderate genetic differentiation among cultivars. Information obtained in this study will provide guidelines for germplasm identification and choice of parent of this species in the future.