| The core of protecting bio-diversity is protection and utilization of geneticdiversity. Allozyme analysis, which is one key methods for studying genetic diversity,can be employed to deduce the frequency of genetic variation in plant population, changes in time and space and their relationship via analyzing the changes in allelenumber and frequency of allozyme loci. In the present research 120 accessions from 4 species and 1 variant species of Eriobotrya, namely, E.japonica Lindl., E.prinoides Rehd. et Wils., E.prinoides var. danduheensis H.Z.Zhang, E.serrata Vidal., and E.dayaoshanensis Chen, were investigated using isoelectric focus in thin-layer polyacrylamide slab gel. In the meantime, trnK gene of 36 accessions was studied via PCR-RFLP.Results of allozyme analysis showed:1. Fifty nine alleles were detected at 24 loci of 12 enzyme systems in 14 populations of Eribotrya with the largest number of five. Analysis of allele frequency variation of 14 populations from E.japonica showed that 15 in 22 loci were significant or extremely significant. As for genetic diversity of 10 populations of E. japonica, average expected heterzygosity (He) and the portion of polymorphic loci (P) were 0.320 and 69.6 respectively, with mean number of alleles per locus of 1.8. Comparison of genetic variation of the populations in E.japonica demonstrated that the population from Fujian had the highest genetic diversity, with He, P and A being 0.350, 77.3 and 1.9 respectively. Fixed indexes of the populations were negative, implying that they had more heterozygous genotypes than expected value of Hardy-Weinberg.2. As far as genetic variation at different loci in 7 populations of E. japonica is concerned, in 19 polymorphic alleles the highest is Aat-2, with Fst 0.280. The average of Fst of the 19 loci was 0.085, in between long-life woody plants and short-life woody plants. Result of Nei genetic similarity (I) showed that among the E.japonica populations, Japanese population and Zhejiang population are the phelogenetically nearest with I of 1.000, while Hubei population and Guangdong population are the phylogenetically remotest with I of 0.931. Moreover, genetic distance between E.japonica and E.prinoides var. daduheensis H.Z. Zhang is the smallest with D of 0.187, while D between E. japonica and E.dayaoshanensis Chen, is 0.336.3. Cluster analysis, with BIOSYS-1 population analysis and NYSYS-pc species analysis,showed that in the dendrograms Japanese population was first clustered to Zhejiang loquat, that all of the species in E.japonica were clustered together and then to E.prinoides var. daduheensis H.Z.Zhang., that E.prinoides Rehd. et Wils. was first clustered to E.serrata Vidal. and then to E.prinoides var. daduheensis H.Z.Zhang, that the cultivars flowering in autumn and winter were clustered together and then to the cultivars in E.prinoides var. daduheensis H.Z.Zhang, flowering in spring. Similar results were obtained from the two methods which, at the level of gene inheritance, confirmed that Japanese loquat was introduced from Zhejiang province of China, and that E.prinoides var. daduheensis H.Z.Zhang, was a relatively independent population that was located in between E.japonica and E.prinoides. Rehd. et Wils. and served as a link for binding E.japonica and the others in Eriobotrya, which supports the simple classification system of Chinese Eriobotrya plants put forward by the late Mr Zhang HZ. The results provide scientific information for ascertaining the origin of loquat, studying the evolutionary events and planning the conservation strategies.4. The 120 accessions could be distinguished by 11 enzyme systems. The mainly good-quality cultivars could be differentiated from the others with their distinct zymograms, which paves the way for cultivar identification and hold potential for extending superior cultivars and protecting the fruit grower's right and interest. Results of PCR-RFLP of trnK gene demonstrated that trnK gene of chloroplastgenome could not be utilized to analy...
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