Population Genetic Analysis And QTLs Study Of Frond Length And Width For Saccharina Japonica

With aim to promote the genetic improment of Saccharina japonica, marker primers development, population genetic analysis, genetic map construction, QTL analysis for main economic traits as well as linkage marker identicification were conducted, and the main results were as following:1) Development of EST-SSR marker for S. japonica and Laminaria digitata. A total of 58 and 83 EST sequences containing SSR were hunted from EST database of S. japonica and L. digitata, based on which 15 and 23 EST-SSR marker primers developed for the two kelps respectively.2) Population genetic analysis for S. japonica. Using SSR markers, population genetic analysis for representative germplasm resources of S. japonica showed that: while both of the genetic diversities in wild and cultivated populations were medium-high, the genetic diversity in wild populations was much higher; genetic differentiation between wild and cultivated populations is significant, but whatever within wild or cultivated populations the genetic differentiations were both medium-low; the germplasm genetic basis consisted of the S. japonica cultivars, S. japonica wild populations, and the crossbreed of S. japonica and L. longissima.3) Construction of molecular linkage map for S. japonica. Using the AFLP and SSR makers, the molecular linkage map of S. japonica was constructed in F2 mapping population. This map spanned 1811.1 cM with an average marker interval of 6.7 cM and covered the 82.8% of the estimated genome of 2186.7 cM4) QTL analysis for traits of frond length and width of S. japonica. For frond length, 3 QTLs explaining in total of 42.36% of the phenotypic variance were mapped, the gene actions of which were additive and partial dominant. For frond width, 2 QTLs accounting for the total of 36.39% of the phenotypic variance were identified, and the gene action of these QTLs was partially dominant.5) Identification and verification of linkage marker of S. japonica frond length. Using BSA method, the marker FL-569 linked to the longer frond was identified. Linkage analysis proved that FL-569 linked to the main QTL controlling frond length and verification results showed that success rate of this marker detection on the S. japonica with longer frond was over 80%.