Genetic Diversity And Relationship Of Half-sib Tea Cultivars Related To Fuding Dabaicha And Yunnan Dayecha

The tea (Camellia sinensis (L.)0. Kuntze) is originated from China, and China is the earliest nation which utilizes and cultivates tea. Tea genentic resources are very rich in China. Fuding Dabaicha and Yunnan Dayecha are the excellent genetic resources of tea breeding, which are two major parents of new green tea and black tea cultivars. The concept of half-sib in woody plant breeding and genetic improvement was used in this study. The phenotypic diversity, genetic diversity and genetic relationship of 40 representative half-sib tea cultivars related to Fuding Dabaicha and Yunnan Dayecha cultivars (strains) were investigated and analyzed using phenotypic characteristics, ISSR and EST-SSR markers. The ISSR and EST-SSR efficiency and effect of polymorphism analysis were compared and analyzed.1. Phenotypic diversity of half-sib tea cultivars related to Fuding Dabaicha and Yunnan DayechaThe biological characteristics, twenty-six descriptive traits and eighteen numberical traits indexs of forty half-sib tea cultivars related to Fuding Dabaicha and Yunnan Dayecha are surveyed and analyzed. The results showed that the variation and diversity of descriptive traits of half-sib tea cultivars were plentiful and its average genetic diversity index is 0.88. That of numberical traits was 1.87 more plentifull than the former. The genetic diversity of half-sib tea cultivars related to Fuding Dabaicha and Yunnan Dayecha were very high by system identification, and the average diversity index reached 1.29.2. Analysis of the genetic diversity and genetic structure using ISSR marker.The genetic diversity and genetic structure of half-sib tea cultivars related to Fuding Dabaicha and Yunnan Dayecha were analyzed by fourteen ISSR primers. The results showed that the identifiability of different cultivars (strains) by ISSR primers was very strong. The genetic diversity index and Shannon information index of fotry half-sib tea cultivars were 0.35 and 0.52, respectively. The cultivars (strains) of different females could be grouped into different groups, which showed that genetic relationship were close. The genetic relationships between different cultivars were analyzed. The tea cultivars (strains) from same breeding units basically were clustered in the same group. Both different source of same female cultivars (strains) group, and cultivars bred by different breeding institution showed high genetic similarity (0.96). The genetic distance between different cultivars (strains) was very near.3. Analysis for the genetic diversity and relationship with EST–SSRThe genetic diversity and relationship among 40 half-sib tea cultivars related to Fuding Dabaicha and Yunnan Dayecha were analyzed using 28 EST-SSR primers. The polymorphism information contents (PIC) was from 0.13 (108) to 0.79 (TM268), with an average of 0.59, indicating high primer polymorphism. The genetic relationship of groups from either different females or different breeding institution, was basically similar. 4. Comparison of capability and efficiency between ISSR and EST-SSR marker in detecting the genetic diversity.The capability and efficiency between ISSR and EST-SSR markers were compared based on parameters including number of polymorphic loci (NPL) and genetic diversity in half-sib tea cultivars related to Fuding Dabaicha and Yunnan Dayecha. The results showed that the average number of polymorphic loci amplified by each ISSR primers were 17.9, 5.06 times higher than of EST-SSR primers (3.54). The detecting capability of ISSR marker was stronger than EST-SSR marker and the polymorphism information of ISSR marker was higher than EST-SSR marker. The identification ability the cultivars of ISSR marker were strong. However, the efficiency of EST-SSR marker was higher than ISSR marker.The clustering analysis of ISSR and EST-SSR was slightly different. The clustering analysis of ISSR marker were two groups, Fuding Dabaicha as the first group, the rest as the second group. And cultivars derived from Fuding Dabaicha as femal parent were gathered into a sub-group using ISSR marker. The cultivars from Tea Research Institute of the Hangzhou Academy of Agricultural Sciences (TRIHZ for short) and Tea Cultivar Research Institute of Jiangsu (TRIJS for short) were distinguishable. There were four groups in the EST-SSR clustering. The first group is Fuyun 6. Xicha 50 and Juhuachun were gathered into the second group. Pingyun was the third group and the rest in the forth group. In the fourth group, there were two sub-groups. Fuding Dabaicha, Zhenong 129 and Shuyong 906 in one sub-group. In the other sub-group, the tea cultivars from TRIHZ had close relationship.The clustering analysis combining the polymorphic loci of ISSR and EST-SSR divided the 40 cultivars into two groups.The Fuding Dabaicha was the group I, and others were the group II, consistent with the ISSR results. Tea cultivars from TRIHZ and Zhejiang University were distinguishable, but tea cultivars from TRIJS were scattered. This result was similar to EST-SSR clustering.