Genetic Diversity Analysis And Drought Resistance Evaluation Of Several Tea Germplasm

As the proterozoic of Tea(Camellia sinensis(L.)O. Kuntze.), there is a lot of varieties, cultivars in China. During the life of tea tree, much water is needed. But with the effect of the global warming getting stronger, extreme weather is frequent. Many crops are influenced including tea. So it’s needed to improve the drought tolerance of tea. Making full use of existing germplasm to create new drought resistant cultivars is a good way to solve this problem.To provide a premise of tea drought resistant breeding, related genetic analysis and evaluation of tea drought tolerance is needed. The first part of this study is the genetic analysis of 89 tea germplasm resources by SSR(simple sequence repeat) marker. 10 pairs of SSR markers(A18, A28, A38, A55, A56, A58, A76, A80, A90, A211) were used to assess genetic diversity and relationship of Camellia sinensis cultivars. A total of 124 alleles were generated from ten primer-pairs. All the SSR markers showed a high level of genetic polymorphism with a mean of 12.4 putative alleles per locus, the heterozygosity of 0.73 and Shannon Index(I) of 0.61. The clustering results show that the genetic similarity coefficient of 89 cultivars is 0.77-0.89 with a mean of 0.8012. All the cultivars mainly divided to 4 groups and they are not divided according to area. All the Chinese cultivars were clustered based on 4 tea district and it shows that the tea cultivars from Jiangbei is distantly related to cultivars from other districts.The second part of the study is to screen drought resistant germplasm from 21 germplasm resources. Tea leaves anatomy was used to measure the thickness of leaves, the upper epidermis and palisade tissue. The ratio of palisade tissue thickness and thickness of leaves and palisade tissue thickness and sponge tissue were calculated and nondimensionalized. The results show that Zhejiangmuhezhong, Xixiangdahe 5, Niupichaqunti, Guangdonglechangbaimaocha and Fuandabai are drought resistant cultivars while Zhejiangputuofocha, Biyun, Xixiangdahe 6, Soubeizhong and Xiangubaihao are drought sensitive cultivars; others are in the middle.