利用ISSR标记分析福云(半)同胞系茶树品种(系)的遗传多样性和亲缘关系

The ISSR Analysis of Genetic Diversity and Relationship of Fuyun Half-sib Tea Cultivars Derived from Fuding Dabaicha and Yunnan Dayecha

福鼎大白茶和云南大叶茶是茶树育种中的骨干亲本,利用这两个亲本选育了许多优良的品种(系)。本研究利用ISSR标记技术分析了40个福云(半)同胞系茶树品种(系)的遗传变异水平和亲缘关系。14个ISSR引物在供试品种(系)间共扩增出251条谱带,多态性条带的比率为96.4%。引物的PIC值平均为0.94,Rp值平均为29.35,表明引物扩增位点的高多态性和对品种的强辨别能力。40份供试品种(系)的基因多样性指数(H)为0.35,Shannon信息指数(I)为0.52。按母本来源和育种机构对供试品种(系)进行分组分析,结果表明不同品种(系)组间的遗传多样性水平比较接近,遗传变异主要存在于组内品种(系)的个体之间,不同组间基因交流明显。供试品种(系)间的相似系数介于0.52～0.75,根据相似系数矩阵按UPGMA法对40个供试品种(系)进行聚类分析,构建了不同品种(系)间的亲缘关系树状图。福鼎大白茶在树状图中形成单独的分支,在树状图的根基处,其它品种(系)根据遗传距离聚类成不同的类群。来源于同一育种单位的部分茶树品种(系)聚类在同一类群中,但未发现按母本来源区分的独立类群。总之,通过ISSR标记分析,可在基因组水平上进一步了解福云(半)同胞系茶树品种(系)间的遗传变异水平,并进一步明确其亲缘关系,为今后福云(半)同胞系在茶树育种上的有效利用提供依据。

Two tea cultivars, Fuding Dabaicha （FD） and Yunnan Dayecha （YD）, are considered as core parents in tea breeding. Many elite tea cultivars have been bred based on these two parents. In this study, 40 half-sib cultivars related to FD and YD were used to analysis their genetic diversity and relationship based on 14 ISSR primers. A total of 251 bands were scored, of which 242 （96.4%） were polymorphic. The ISSR markers showed high poly-morphic and high distinguishable ability according to their high value of PIC （0.94） and Rp （29.35）. The mean of Nei＇s genetic diversity and Shannon＇s information index were 0.35 and 0.52 among all tested cultivars, respectively. No obvious genetic diversity was found between groups classified by their female parents or breeding institute. A high degree of genetic variation was found between single cultivars within the groups according to the very low value of Gst. The high level ofgene flow （Nm） was revealed among different groups. The pairwise similarity coeffi-cient between the cultivars varied from 0.52 to 0.75, through which a dendrogram of 40 cultivars was constructed. In the dendrogram, the cultivar FD was individually separated from other cultivars. Generally many cultivars originated from the same breeding institute were clustered into the same groups, but no distinct groups were found according to the origin of cultivars parents. This paper provides useful information to deeply understand the genetic variation and relatedness of half-sib cultivars bred with two core parents to help theirs availability in future tea breeding.