Since the successful cloning of the female and male gametophytes of Laminaria japonica in our lab., a new breed “Danhai No.1” derived from a female cell clone b, as been selected and used in the kelp industrial cultivation. Plans to produce hybrid Laminaria have been put into practice for some years.It was to use the clones of different female and male gametophytes for various crosses. After trials, several laminarian hybrids (F1) have been obtained. The hybrid breed “Danza No.10” has been found to be the best, The clones used were FH10 and MHJ. Here FH10 stands for the female haploid clone No.10 and MHJ stands for the male haploid cell clone introduced from Hokkaido, Japan in 1981. The pedigree of the hybrid is as follows: FH10×MHJ→“Danza No.10” When the hybrid was selffertilized it gave broad segregation in the F2, as expected. When the hybrid was compared with the control in productivity it showed superiority. It was estimated to be able to increase 30% yield over the control which is a high productive breed widely cultivated here. The iodine content of the hybrid was rather high too, more than 70‰. Obviously it is much easier to use the Laminaria hybrid in mariculture than to use hybrid rice in agriculture. No male sterility is needed.The main thing is to keep the two cell clones (Which would give rise to F1 heterosis) vigorously in the lab or in the green house.
