A new method of Laminaria japonica strain selection and sporeling raising by the use of gametophyte clones

One-celled female and male gametophytes of three Laminaria japonica strains were isolated, cultured and gametophyte clones were formed. A technique combining strain selection with sporeling raising by the use of these female and male gametophyte clones was studied. Experiments on 9 different crossing combinations was conducted in November of 1997 in Qingdao, P. R. China. The main economic characteristics, frond length and fresh weight, of sporophytes of different crossing combinations were measured. F 1 sporophytes of No. 2 showed a higher fresh weight and longer length, therefore, No. 2 (Wh860 ∔ × Lid) was selected as a good combination. Its parental female and male gametophyte clones are being mass cultured for sporeling production. By this method, the time needed for strain selection was shortened from 5–6 to 2 years. As compared with the routine method of sporeling raising by the collection of zoospores, the time of sporeling ra ising of this method decrease by 50% , and the production cost is also reduced by 50%. It is believed that this method will be labour and time saving and a more economic way for strain selection and sporeling raising in L. japonica cultivation industry.