Studies On Identification And Classification Of Genomic DNA In Prunus Mume By Molecular Biology

This study started from the analysis of morphological characteristics of samples (including 27 flowering Prunus mume varieties, 19 fruiting Prunus mume varieties and 8 varieties between Prunus salicina and Prunus ameniacd) such as leaves and stones, followedby the analysis of RAPD and clustering of the RAPD result. It has revealed that:There were great differences in leaf morphology among P. mume, P. salicina and P. ameniaca. In P. salicina, leaves with a green petiole were long ellipse and wedge-like at the base, with no hair on the surface and petiole. In P. ameniaca, the leaf was rough on the surface and had hair. With its own germplasm characteristics, P. mume was close to P. ameniaca in genetic relationship. In terms of stones, it's easy to distinguish the three categories on account of the fact that P. salicina had a stone that was smooth on the surface and had creases; P. mume had a stone with many dots on the rough surface; and P. ameniaca had a smooth stone. But for varieties of each category, it seemed difficult to make a comparison and classification. ?With the improved method of CTAB, the genomic DNA extracted form plum and other species close to P. mume in genetic relationship could be directly used in PCR amplification, with good results obtained.With 20 primers (screened from 132 primers), 264 fragments had been amplified. With primers of S44, S446 and S456, 17 fragments had been amplified and 9 fragments had been amplified with the primer of S452, with 13.2 RAPD fragments amplified from each primer on the average. The fragments mostly ranged from 400 to 2500 bp.The bands amplified with different primers were totally different. Clustering analysis showed that plants in the genus of P. salicina could be distinguished from those in the genus of P. ameniaca; there was some genetic relationship among P. mume, P. salicina and P. ameniaca, of which P. ameniaca was closer to P. mume in genetic relationship; and the distance between varieties of each genus was different, with the smallest being 0.1138 and largest being 0.7633. The genetic distance reflects genetic relationship between tested materials. The result that varieties of each genus were close to each other in genetic relationship testified the traditional morphology-based taxonomy from the genomic DNA.On the basis of RAPD results, it's different to make an identification among flowering P.mume, fruiting P. mume and their varieties, while Primus cerasifera is relatively easy to identify such categories as P. mume, P. salicina and P. ameniaca. Therefore, it could be said that P. cerasifera is another category.This study testified the morphology-based taxonomic result for P. mume and the species close to P. mume in genetic relationship. But it could not provide sufficient testimonies for taxonomy below genus. It has been proved that RAPD technology could be used in identification and taxonomy between genera. On the premise that primers are properly selected and experimental conditions are stable, the results are repeatable well and could be used in identification of the specific varieties.In the thesis, the feasibility for application of RAPD technology to the taxonomy and identification of P. mume and species close to plum in genetic relationship, the RAPD problems existing in systematics and the taxonomic position of Prunus cerasifera and peach-shaped plum were also discussed.