Breeding of the new Saccharina variety Sanhai with high-yield

Backcrossing, self-crossing and target region amplified polymorphism (TRAP) marker assisted selection were utilized to breed a new Saccharina variety in this work. After two continuous cycles of backcrossing using Fujian as the recurrent parent and three cycles of self-crossing, the new high-yield variety Sanhai with stable excellent traits was obtained. During the whole Saccharina growth period (from January to April), the blade length and width of Sanhai were always significantly larger than Fujian as the control at the level of 0.05, displaying the obvious growth advantage of the new variety. In addition, the blade width and fresh weigh of Sanhai have reached 32.69 +/- 3.36 cm, 686.82 +/- 80.45 g respectively which both superior to its two parents (Fujian 25.22 +/- 4.34 cm, 508.51 +/- 96.27 g and Rongfu 24.59 +/- 3.58 cm, 521.23 +/- 68.13 g). For this breeding process, TRAP combined with phenotypic traits analysis was used to select the second generation of backcrossing (BC2F1) for subsequent self-crossing. The gene diversities of Sanhai obtained in this work (H = 0.1572) and Fujian (H = 0.1687) were lower than that of Rongfu (H = 0.2303) on the basis of TRAP markers, which showed the outstanding genetic stability of the new variety. The results of Unweighted Pair-Group Method with Arithmetic Mean (UPGMA) cluster indicated variety Sanhai could be distinguished from Fujian and Rongfu and the genetic structure of new variety was stable.