A Study On Variation Patterns In Malus Baccata(L.) Borkh.

Malus baccata (L.) Borkh. has the most extensive distribution and complicated variability. The study of genesic history and variation patterns of this species redound to understand the variation and genetic diversity of the genus Malus Mill., and to probe into the origin, migration and distribution patterns of the genus Malus Mill. During the study, more than 500 specimens from main herbariums in China were checked, and almost 1000 specimen photos were shot. The herbariums visited by the author in 2006 were PE, NAS, N, NF, HHBG, SXU, NEFI and so on. Based on those works, a series of field investigation and collection were carried out in Mt. Zhongtiaoshan, Mt. Lingkongshan, Mt. Wutaishan and Mt. Guancenshan of Shanxi Prov., Mt. Donglingshan of Beijing, Mt. Saihanba of Hebei Prov., Mt. Changbaishan of Jiling Prov., Mt. Xiaoxinganling of Heilongjiang Prov., Mt. Tianmushan of Zhejiang Prov., and Mt. Huangshan of Anhui Prvov. More than 300 specimens were collected, 8 populations with 200 specimens which were chosen from all specimens were studied in order to detect the varition law among and within populations by means of morphology, ISSR molecular marker and numerical taxonomy. The main research results were as follows:1. The morphological and genetic variation among and within populatons in M. baccata were studied by systematic analysis for the first time, which found the general rule of phenotypic characters with geographical distribution. The genetic stucture, diversity and the relationship of populations were detected in M. baccata by ISSR.2. The leaf venation order characters of M. baccata were reported for the first time: its second venation belonged to brochidodromous; the second venation branch displayed brochidodromous; the thin secondary veins were found in leaf base. Compared the vein variation pattern with M. baccata, M. hupehensis, M. doumery and M. parahupehensis, the genesis geologic time of M. baccata was concluded.3. The rank of infraspecific taxon in M. baccata were coordinated for the first time. The relationship of varieties were ascertained. A new variety namely M. baccata var. guancenshanensis were discovered. A practical taxon key were compiled by characters mainly from flower.4. The geography distribution patterns were comprehensive and systematic studied in M . baccata, and the new distribution records were supplemented. The distribution patterns of M. baccata was drawn, of which disjunction and island distribution were existent obviously. The reasons for this distribution were analysed. Furthermore, the law of distribution pattern with morphological evolution in M. baccata was also discussed.5. The speciation and differentiation process of M. baccata and its related species were inferred by the comprehensive analysis from ISSR molecular marker, karyotype of the genus Malus Mill., peroxidase isozyme patterns to leaf vention orders of M. baccata. Finally, the research revealed the vicarism of M. baccta, M. hupehensis, M. rockii and M. mandshurica in geographical distribution.