The Introduction Of Ornamental Apple And The Analysis Of DNA Fingerprint In Malus Genus

1. Seventy Eight species and cultivars in Malus genus were introduced from abroad. The morphological characteristics, cold of hardiness, drought resistance, waterlogging tolerance and the occurrence and control of pests and diseases were studied. A system for evaluation of ornamental apple cultivar was set up and used in selecting 37 species and cultivars. Propagation methods and cultivation techniques of ornamental apple were studied.2. Amplified Fragment Length Polymorphism (AFLP) analysis was used to reveal the relationships of species in Malus. A total of 72 samples representing 34 species, varieties, and hybrid species, and 38 cultivars and an outgroup were assayed. Six pairs of primers combinations selected from 64 combinations tested produced 1,692 legible loci, of which 1,547 (91.4%) were polymorphic. The genetic similarity coefficient among these 72 samples varied from 0.54 to 0.82. Four groups of taxa were really recognizable based on the results of cluster analysis. First one is Malus florentina. The second clade contains the taxa of Sect. Choromeles. And the third includes the taxa of Sect. Docyniopsis. The taxa in Sect. Sorbomalus, Sect. Gymnomeles and Ssect. Malus of Malus gather in clade fourth. All cultivars of apples and flowering crabapples distributed in Asia into the last two clades. The wild species in Asia played a very important role in the development of cultivars in Malus. A new section (Sect. Florentinae Cheng M. H.) is supportedproposed based on by AFLP result. The Ssect. Sorbomalus and Ssect. Gymnomeles are merged into Sect. Malus (except Malus florentina).3. TRAP (Target region amplification polymorphism) was applied to elucidate relationships in Malus genotype in this article. TRAP is a novel PCR-based molecular marker technique which uses gene-based information for primer design. 42 Malus samples of 27 species, varieties, 8 hybrid species and 7 cultivars were chosen for using TRAP maker system analysis. Two fixed primers, designed by using matK gene sequences of Malus sieboldii, paired with two arbitrary primers, were used to apply TRAP PCR. A dendrogram was generated using the UPGMA method of the SAHN function depends on a total of 197 unambiguous bands of which 182 were polymorphic with an average of 45 polymorphic bands per primer combination and the percentage of polymorphic bands was 92.4%. The bands ranged in size from 75 to 700 bp. On the basis of TRAP PCR cluster analysis revealed that the closer relationships in the dendrodram of Malus samples are in agreement with the origin of these genotypes. TRAP is a potentially useful marker technique for genetic diversity studies in Malus genus.