浙江洞头不同羊栖菜品系的形态特征及1个代表性养殖群体的AFLP分析

Morphological comparison of different cultivated strains and AFLP analyses of a typical cultivated population of Hizikia fusiformis at Dongtou,Zhejiang

2007年对中国羊栖菜(Hizikia fusiformis)主产区浙江省洞头县12个羊栖菜养殖品系的重要形态特征和经济性状进行了比较研究,并利用AFLP技术对1个典型养殖群体的遗传多态性进行了分析。结果显示,这12个品系在全长、全湿质量、侧枝长、侧枝湿质量、侧枝密度等方面存在显著或极显著差异(P<0.05或P<0.01)。8对AFLP引物组合在这个典型羊栖菜养殖群体的27个随机挑选的个体中扩增出198个片段,其中多态性片段为166个,多态位点比率为83.8%。平均每对引物扩增的片段为24.8条。根据个体间的Nei遗传距离,以UPGMA法构建了个体间的系统树图,27个羊栖菜个体聚为一枝,作为对照的铜藻为另一枝。本研究从形态与DNA分子水平说明了浙江洞头羊栖菜养殖群体具有高度遗传多态性。

The brown seaweed Hizikia fusiformis has been one of the five major farmed algae species along the Chinese coast. In recent years, mass production of zygote-derived seedlings by use of synchronization technique has been well established and successfully applied under commercial cultivation conditions. This technique advance makes cultivation of this alga more sustainable and lays the foundation for future breeding work. The principal cultivation ground of H. fusiformis in China is at Dongtou county, Zhejiang province. The farmed population in that region is a mixture of different geographical populations collected along the Chinese coast. Up to now, there has been no report on fundamental biological information of this farmed population. The principal goal of this investigation is to analyze morphological variations among different strains and assess genetic polymorphism of a representative population. Totally 12 strains were collected and six characteristics were measured including total length, total wet weight, branchlet length, branchlet wet weight, branchlet density and the number of receptacles per branchlet. Meanwhile, twenty-seven individuals were randomly sampled from a representative population for genomic DNA isolation and AFLP analyses to assess genetic polymorphism. Morphological analyses revealed significant differences among these 12 strains in terms of total length, total wet weight, branchlet length, branchlet wet weight and branchlet density （P〈0.05 or P〈0.01）. In AFLP analyses, by using eight pairs of primer combinations in the representative population including EcoRI-AAC/MseI-CAA, EcoRI-AAC/MseI-CAC, EcoRI-AAC/MseI-CCA, EcoRI-AAC/MseI-CCT, EcoRI-AAG/MseI- CAA, EcoRI-AAG/MseI-CAC, EcoRI-AAG/MseI-CAG, EcoRI-ACC/MseI-CAA, a total of 198 DNA fragments were amplified, of which 166 were polymorphic. The percentage of polymorphic fragments was 83.8% and the number of amplified fragments ranged from 15 to 38 with an average of 24.8 for each primer combination. Based on Nei＇ s genetic distance individual-wise dendrogram was constructed by use of UPGMA cluster analysis, from which it was presented that 27 H. fusiformis individuals clustered into one clade and the individual of Sargassurn horneri clustered into another one. The morphological characteristics selected in this study were closely related to commercial production and could be used as reference for future studies. The most important result of this study is the high polymorphism detected in the farmed population. High polymorphic parental resources provide valuable basic materials for breeding of new varieties.