| As one of regions from which tea plants originated, Sichuan and Chongqing region provided with lots of excellent cultivars (strains) because of natural selection and artificial selection. With a better understanding of genetic diversity and relationship of the tea cultivars, we could try to get rid of our blindness and increase efficiency in the course of breeding work. A result of fact that RAPDs and ISSRs could indicate straightly genetic diversity at the level of DNA and avoid the effect of difference of organizes, growth periods and environment, the two techniques had been applied broadly to investigate the relationships between tea cultivars. In the study, RAPDs and ISSRs were used to analyze a total of34cultivars accessions derived from the region of Sichuan and Chongqing, aiming at providing theory evidence and foundation that we make better use of tea plants germplasm resource and choose better cross parent at time of breed improvement. The results were as follows:1The RAPD analysis on genetic diversity and relationship of cultivars in Sichuan and Chongqing:(1)23effective primers screened from72RAPD primers, which amplified314loci, of which,291are polymorphic and the percentage of polymorphic loci is92.68%, the mean PIC value is0.88. The selected RAPD primers amplified bands varied ranging from7to19and the mean value is13. The percentage of polymorphic bands varied ranging from66.7%to100%and the amplicons band size varied ranging from200to4500bp, of which, most varied ranging from500to3000bp.(2) The genetic similarity coefficient between34materials ranged from0.618to0.710. We used UPGMA method based on genetic similarity matrices to divide the34materials to two parts, of which, Shuyong series with parent lines Yunnan dayecha, Tianfucha28, Tianfucha36and Nanjiang3get together and the rest22selected from breeds in Sichuan region get together.2The ISSR analysis on genetic diversity and relationship of cultivars in Sichuan and Chongqing:(1) We chose23good-effective primers from65ISSR primers prepared to amplify the template DNA.262amplicons were gained, of which,238are polymorphic, the percentage of polymorphic amplicons is90.84%, the mean value of PIC is0.87. The number of amplified amplicons varied ranged from7to18, the number of amplicons per primer is11, the percentage of polymorphic primers varied ranged from62.5%to100%, the amplicons band size amplified varied ranged from200to4500bp, of which, the most varied ranged from250to1000bp.(2) The genetic similarity coefficient between materials varied ranged from0.584to0.935, of which, the mean value is0.678. We used UPGMA method to divide the materials studied into two parts, of which,10materials consisted of Shuyong series but Shuyong906and Tianfucha24, Tianfucha28, Tianfucha36get together, the rest were divided into two, of which, Tianfucha11and Yucha1get together, the rest included22materials get together.3The combination of RAPD and ISSR analysis on genetic diversity and relationship of cultivars in Sichuan and Chongqing:(1) The genetic similarity coefficient between materials studied varied0.616-0.948based on the data set composed of RAPD and ISSR data, the mean value is0.695. Result show that:34materials studied were divided in two parts, of which, Shuyong series cultivars with parents lines Yunnan dayecha get together, the rest selected from Sichuan lobular-tea plants. The analysis result above is fairly similar to the results based on RAPD and ISSR data, which is more similar to ISSR rather than RAPD.(2) The mantel’s test were done on genetic similarity coefficient between RAPD and ISSR. Results show that the correlation between RAPD and ISSR appeared significant (r=0.772), which confirmed a high stability of RAPD and ISSR techniques. They are optimized and coherence reliability in studying genetic diversity. In summary, Mingshan213and Shukelian1with parents lines Fuding dabaicha get together with cultivars in Sichuan at first, while Tianfucha11and Tianfucha28who come from the same locality don’t get together first. From the top, the relationship between breeds/strains has no necessary connection with geographical origin. |
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