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 co mbining strain selection with sporeling raising by the use of these female and male gametophyte clones was studied. Experiments on 9 different crossin g combinations was conducted in November of 1997 in Qingdao, P. R. China. T he main economic characteristics, frond length and fresh weight, of sporoph ytes of different crossing combinations were measured. F-1 sporophytes of N o. 2 showed a higher fresh weight and longer length, therefore, No. 2 (Wh86 0 + x Lid) was selected as a good combination. Its parental female and male gametophyte clones are being mass cultured for sporeling production. By th is 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 col lection of zoospores, the time of sporeling raising of this method decrease by 50%, and the production cost is also reduced by 50%. It is believed tha t this method will be labour and time saving and a more economic way for st rain selection and sporeling raising in L. japonica cultivation industry.