Study On Genetic Analysis Of Taxodium Rich. Using RAPD

Genetic diversity of 18 material of Taxodium Rich, conserved in Jiangsu Province and Chinese Academy of Sciences Institute of Botany was researched by RAPD. The results are as flows:1. Compared two methods of DNA extraction:SDS and CTAB. DNA sample extracted by these two methods were all of good quality for RAPD.Comparatively. But the method of CTAB obtained higher purity DNA sample.2. Optimized RAPD reaction system and suitable conditions was obtained: IX buffer, 2.5 mmol/L MgCl2, 0.25 mmol/L dNTPs, 24 ng primer, 20-40 ng template DNA, 1.2 U Taq DNA The total reaction volume was 20 μl.Reaction program was: 94℃ 4 min, 94℃ 0.5 min, 36℃ 1 min, 72℃ 1.5 min, 45 cycles; 72℃ 7 min.3. 100 arbitrary 10 bp primers were used for amplification, among which 13 better primers were selected for RAPD analysis. These primer could amplify stable and polymorphic RAPD bands. 92 reproducible amplified fragments which were 500-3000 bp long were obtained. 75 bands were found to be polymophic. It showed that Taxodium Rich. had enrich genetic diversity.4. According to the cluster analysis, the results showed that the genetic relationship between Taxodium distichum Rich, and T. ascendens Brongn. is nearer; the genetic relationship of first crossed generation(F₁) Taxodium 'zhongshansha 302' [Taxodium distichum (Linn.) Rich.×T mucronatum Tenore] is closer to the female parent Taxodium distichum (Linn.) Rich.. When the threshold is 5.0, the first backcrossed generations(BCF₁) belong to 3 groups: BCF₁149 is the first group; BCF₁102 is the second group; BCF₁1, 27, 118, 140, 86, 136 formed the third group, the clustering results were in consistence with that of the analysis of morphology. BCF₁149 might be used as the type of fast-growing ornamental forest. BCF₁118 and BCF₁102 might be used as the type of fast-growing timber...