| Cotton,as the main economic crop,plays a decisive role in the development of national economy.The regional testing of national cotton varieties plays an important role in the authenticationof new cotton varieties.It is a scientific basis for the evaluation and promotion of cotton varieties by using multi-year and multi-location tests to identify new cotton varieties.In this study,241 cotton varieties approved in Xinjiang and 255 cotton district tested lines from 2020 to 2021 in Xinjiang Uygur Autonomous Region were selected as research objects.The fingerprinting of 241 cotton approved varieties was constructed using screened SSR molecular markers,and the purity and authenticity of all district tested lines were identified.This study provides a basis for the authenticity identification and verification of cotton tested lines,and provides a reference for the breeding of new cotton varieties in Xinjiang.The main results are as follows:(1)Construction of reference fingerprinting of approved varieties:In this study,61 SSR markers with high polymorphism and clear amplification bands were screened out from more than 200 genome-wide markers,and 145 polymorphic loci were amplified from 241 approved varieties,resulting in a reference fingerpring map composed of 35186"0-1"data.Cluster analysis showed that at least 12 markers could be used to distinguish the 241 varieties completely,and a total of 35 loci were amplified from the 12 markers,and the"0-1"data of 12 markers were integrated to obtain identification fingerprinting of the 241 varieties,which could be used for variety identification.(2)Purity identification of the tested lines: In 2020,there were a total of 102 lines for testing and were divided into four series: 35 Xinluzao,54 Xinluzhong,6sea-island cotton and 7 color cotton lines.In 2021,there were 153 lines including 61 Xinluzao series,76 Xinluzhong series,10 sea-island cotton and 6 color cotton lines.Forty-eight seeds were randomly selected from each line to extract DNA.Four typical polymorphism markers for each series were used for purity identification,and more than 20 polymorphic loci were amplified on average.The purity of each line was calculated by single locus average method,and the statistical results of gel bands showed that the purity of the tested lines in 2020 ranged from 88.5% to 100% with an average of 94.3%,and the purity of 5 lines were lower than 95%;the purity of 153 tested lines in 2021 ranged from 68.3% to 100% with an average of 81.7%,and the purity of 61 lines were lower than 95%,which was significantly lower than that in2020.(3)Authenticity identification of tested lines: The tested lines were amplified using 61 markers.Combined with the fingerpinting map of the approved varieties,cluster analysis and genetic similarity coefficient analysis were performed by NTSYS software.The results showed that the genetic similarity coefficient of Cai 1 and Cai 4was 0.991,which was suspected to be similar lines;the genetic similarity coefficient of Chang 2,Chang 5,Chang 6 and Chang 8 was 0.991,which was suspected to be similar lines;the genetic similarity coefficient of Chang 3,Chang 4,Chang 7 and Chang 9 was 0.991,which was suspected to be similar lines;The genetic similarity coefficients of A9 and C3,A2 and A12,C17 and F4,D4 and D20,E18 and E19,E6 and E10,D8 and E13 were approximately 0.999 for each pair,which also were thought to be similar lines.(4)Genetic diversity analysis of tested lines and approved varieties:The approved varieties and tested lines were separated when the genetic similarity coefficient was 0.46 to 0.78,indicating that the genetic difference between the tested lines and the approved varieties was large.At the same time,when the genetic similarity coefficient was 0.52,the biennially tested lines were divided into two groups,indicating that the biennially tested lines were far from each other and had rich genetic diversity.The results showed that cotton breeders have paid more attention to introduce more genetic variation while improving the target traits,so as to further promote the improvement of varieties. |
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