Study On The Application Of RAPD Molecular Markers To The Relationship Among Watermelon Materials

26 materials coming from Sichuan Agricultural University were used in this study. We investigated and statistically analyzed the biological characters,and extracted the genomic DNA by improved CTAB method. In the paper,the reaction system of RAPD were optimzed and the suitable primers were screened, and cluster analysis were performed according to their genetic distance.The resutls as following:1.The biological characters of these 26 watermelons were investigated and statistically analyzed through field and labtorary experiments.The results showed there were some differences in the pour rattan stage, blooming stage, fruit setting node, fruit number, fruit type,fruit heavy, peel hardness, peel color, flesh color, peel thickness, the boundary of peel and flesh, seed size,seed number seed color,TSS etc among these materials.2.26 watermelon materials genomic DNA were extracted by improved CTAB method and SDS method. The results showed the improved CTAB method would be better. OD260/OD280 of DNA was 1.83-2.11, and DNA quality was high that could be used for RAPD amplification.3.The optimal RAPD-PCR system of watermelon was established with orthogonal experiment design. The optimized PCR amplification system was 1×Buffer,0.4μmol/L primer,1.5mmol/L Mg2+,2.5 U Taq enzyme,250μmol/L dNTPs,10 ng/μl template DNA,add ddH2O to terminal volume 25μl. The suitable PCR procedure was one cycle denaturing at 94℃5min,40 cycles which involves denaturing at 94℃for 30s,annealing at 37℃for 30s and extending at 72℃for 1 min,one cycle extending at 72℃for 7min.4.The analysis of the 26 watermelon materials with 3 RAPD primers which were screened from 60 random primers generated 56 bands,with an average of 18.67 bands per primer. And 51 (91.07%) of them were polymorphic, with an average of 17 polymorphic bands per primer.5. Using DPS software to deal with all date, and the genetic distance was analyzed by genetic distance method. Cluster analysis indicated the genetic distance of 26 materials was 0.1628-0.5694, and all the materials could be divided into eight groups with the similarity coefficient at 0.31.They were respectively one North China ecogeographic group, one East China group, one Japan group, one Northwest China group, one American group, one South China group and two medial groups.