title: Trait evaluation and trial cultivation of Dongfang No. 2, the hybrid of a male gametophyte clone of Laminaria longissima (Laminariales, Phaeophyta) and a female one of L. japonica.
abstract: Direct cultivation of the first filial generation of gametophyte clones from different Laminaria species is a highly effective way of utilizing kelp heterozygous vigor (heterosis). A male gametophyte clone of L. longissima Miyabe and a female one of L. japonica Areschoug were hybridized, generating Dongfang No. 2 hybrid kelp. This hybrid kelp was used directly in trial cultivation, and its agronomical traits were evaluated. L. longissima and L. japonica are obviously different and complement each other in their morphological characteristics and ecological performances. The hybrid of their gametophyte clones, Dongfang No. 2, showed 56.8% heterozygous vigor in yield. It also showed increased yields of 41.0 and 76.4% compared to the widely used commercial kelps Variety 1 and Variety 2, respectively. In large-scale cultivation trials at different locations and in different years, Dongfang No. 2 attained significantly higher yields than Varieties 1 and 2, increasing yield by 26.4% on average over Variety 1 and by 65.0% over the other. Dongfang No. 2 has a robust holdfast and a wide, long and deep-brown uniform blade, which shows a distinct middle groove. In addition to yield, Dongfang No. 2 also demonstrates obvious heterozygous vigor in other agronomic traits. It is resistant to strong irradiance, as the two commercial varieties are, has an appropriate vegetative maturation time, and adapts well to a range of different culture conditions. The parentage analysis using AFLP of total DNA and SNP of the ITS region of ribosomal RNA transcription unit showed that Dongfang No. 2 is the real hybrid of L. japonica and L. longissima.
authors.forename: Xiaojie
authors.initials: X
authors.lastname: Li
authors.forename: Yizhou
authors.initials: Y
authors.lastname: Cong
authors.forename: Guanpin
authors.initials: G
authors.lastname: Yang
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Shi
authors.forename: Shancun
authors.initials: S
authors.lastname: Qu
authors.forename: Zhiling
authors.initials: Z
authors.lastname: Li
authors.forename: Guowen
authors.initials: G
authors.lastname: Wang
authors.forename: Zhuangzhi
authors.initials: Z
authors.lastname: Zhang
authors.forename: Shiju
authors.initials: S
authors.lastname: Luo
authors.forename: Hongliang
authors.initials: H
authors.lastname: Dai
authors.forename: Jianzu
authors.initials: J
authors.lastname: Xie
authors.forename: Guangliang
authors.initials: G
authors.lastname: Jiang
authors.forename: Jialiang
authors.initials: J
authors.lastname: Liu
authors.forename: Tongyong
authors.initials: T
authors.lastname: Wang