Abstract:A method for early production of large-size Sargassum thunbergii seedling in north China was developed, which consisted of procedures such as 50 d advancement of seed collection, timesaving of indoor cultivation and accelerated artificial maturation of broodstock thalli. This method should be used in combination with a set of off-shore mariculture and management techniqes. It is applicable in north China as proved by trials for three consecutive years. About 33.737 million healthy seedlings with uniform size were bred with this method, which grew into vertical young thalli (4~6 cm in length) with 3~4 branches after being cultured off shore for over three months. This method overcomes the difficulty of breeding large-size seedlings met in previous S. thunbergii seedling production practice, and will certainly facilitate the large scale seedling production and cultivation of S. thunbergii.
