9个海带栽培品种自交系后代遗传多样性和亲缘关系的AFLP分析

Genetic analyses of principal farmed cultivars of Laminaria japonica in China:AFLP analyses of selfbreeding F_1 of nine cultivars

于2007-2008年采集养殖生产中使用的海带烟杂和单克隆海带配子体杂交培育的东方3号等9个海带(Laminaria japonica)品种/系成熟孢子体,采集游孢子后,通过人工育苗获得自交子一代。以青岛野生海带自交子一代作为对照,运用AFLP分子标记技术对以上10种海带幼孢子体进行遗传多样性和亲缘关系分析。用10对引物组合共扩增条带434条,其中多态性带141条,多态性平均检出比例32.5%。UPGMA聚类分析,可将10个海带品种/系自交子一代分成三大类群(相似系数0.87)。其中90%受试海带品种/系亲本的纯合性较高,自交系个体后代遗传相似系数在0.97以上。分析结果表明,中国北方栽培海带品种/系与青岛的野生海带可能来源于同一种群,而福建的栽培海带则在亚热带水域长期栽培后特化成一个相对独立的地理种群。早厚成海带和真海带之间有较近的亲缘关系,推测早厚成海带的亲本可能是真海带。而烟杂海带亲本杂合度明显高于其他海带品种/系,从品种的角度考虑,还需进一步筛选纯化。

Laminaria japonica has been a commercially important farmed seaweed in the history of the Chinese marine aquaculture.Much effort has been put into breeding new cultivar in practical production throughout the farming history.These cultivars have been generated through different breeding methods by use of different parental plants and were demonstrated to be more productive,resistant to disease and high temperature.As a result,the cultivation of L.japonica has been greatly facilitated.However,in most of the published results,the characteristics of these cultivars were described by morphological indexes.The genetic relationship between different offspring and the parental plants of these cultivars are largely lacking. Under this background in this investigation in the year 2007 to 2008,we have sampled 9 principal cultivars of this species and conducted AFLP analyses of the selfbreeding offspring of 9 cultivars.Totally 100 DNA samples from 100 offspring individuals were analyzed.A wild Qingdao population living at the southern distribution limit in China（latitude：36 N）was taken as a control.Totally,434 loci were obtained using 10 combinations of selective primers.Of these loci,141 were polymorphic, accounting for average 32.5%of the total.When integrated with the UPGMA dendrogram of offsprings,10 Laminaria lines can be clustered into three major groups（the coefficient of similarity is 0.87）.The results showed that all the parental plant except YanzaweremostlygeneticallyhomozygousevenincludingthelinessampledfromQingdaowildpopulationreachingacoefficient of similarity 0.97.Cultivars derived from subtropical Fujian province have developed into more or less a distinct population as confirmed by relatively far distance from all the northern cultivars.The cultivar Yanza showed highest level of heterozygosity in alltheparentalplantsindicating thatmoreselection workneedstobecompletedin thiscultivar.Toour acknowledge,thisisthe first report to analyze selfbreeding offspring of the cutlivars in a farmed alga by use of AFLP.