Study On Genetic Relationship In Tomatoes By RAPD

This experiment uses RAPD molecular marker to analyze the genetic diversity of15tested tomato varieties in order to determine the genetic relationship of these species. The results were as follow.The modified CTAB method is used to to extract genomic DNA of the tested tomato varieties. The OD260/OD280is value between1.7to1.9, and the DNA agarose gel electrophoresis band is clear. It suggests that the DNA is of high purity and good quality. DNA can fully satisfy the requirements of RAPD markers. Preliminary experimental set up of reaction system and amplification procedures is applicable to the test. The reaction system of tomatoes:2.0uL10×PCR buffer,0.25mM·L-1dNTPs,2.0mM·L-1MgCl2,1U Taq polymerase,15ng·ul-1random primers,40ng of DNA. The amplification program:pre-denaturalization5min at94℃, denaturalization1min at94℃, renaturation1min at36℃, and extending90s at72℃for35cycles, finally extending10min at72℃.1%agarose gel electrophoresis is used to detect the amplification products, in order to obtain polymorphism, reproducible bands. Using the NTSYS software to analyze test data, we can get the test material genetic similarity coefficient and clustering tree.15tomato tested varieties were divided into four groups. The first group-No.1, No.2, No.3, No.4, N0.6, N0.8, No.9, No.10, No.11, No.12, No.14, No.15; The second group-No.5; The third group-No.7; The fourth group-No.13. The range of genetic similarity coefficient of the tested material is0.61to0.92, with an average similarity coefficient of0.76, the genetic distance of only0.24. This shows that the genetic diversity between the tested tomato varieties is at a lower level, indicating that the tested tomato varieties have a closer relationship.14of15tomato materials’ average genetic similarity coefficient is between0.73-0.80, with an average of0.77. It shows that the genetic diversity of tested tomato varieties is relatively poor. And the tomatoes’genetic background is relatively narrow. The highest average genetic similarity coefficient is No.9and No.11, and the average similarity coefficient is0.8. The lowest average genetic similarity coefficient is No.13, and the average similarity coefficient is0.68. The genetic similarity coefficient of No.6and No.11is of0.92. The genetic distance is of0.08. It indicates that their genetic relationship is close. The genetic similarity coefficient of No.3and No.13is same as it is of No.13and No.15.Their genetic similarity coefficient is0.61. And the genetic distance is0.39. It indicates that their genetic relationship is very far.