Genetic Diversity Of Dendranthema By Isozyme Analyses

Dendranthema grandiflora Kitamu (Asteraceae) is one of ten traditional famous flowers in China and four cutted-flowers in the world, and it can be served as ornamental plants, edible vegetables and medicinal materials. China is the origin of chrysanthemum cultivars. It is reported that eighteen species are distributed and the number of cultivars are more than 3000 in China. So the research of Dendranthema grandiflorum is very important. The genetic diversity of 148 samples belonging to 8 species (e.g. D.indicum, D.zawadskii, D.chanetii, D.lavandulifolium, D.dichrum, D.vestitum, D.nankingense, D. grandiflorum) was investigated using peroxidase isozyme (POD) and esterase isozyme (EST) for researching on the relation among species and cultivars, the classify and the origin of cultivars in D. grandiflorum.The main results are listed as follows:1. The genetic diversity of 148 materials in 8 species of Dendranthema was studied based on the polymorphisms of POD and EST isozyme. A total of 16 POD bands and 15 EST band from 12 isozyme loci were obtained.2. POD and EST of chrysanthemum were tissue specific and process specific. In the young leaf, old leaf, young stem and old stem, the isozyme band of young leaf was the most, and the isozyme band of old stem was the least. The number of POD band during the vegetative stage was more than that during the reproductive stage, while the EST band during the same stage was clearer.3. The genetic variation of cultivars in D. grandiflorum was very high, and the effective numbers of alleles per locus (A), percentage of polymorphic loci (P) and heterozygosity (Ho) among all the cultivars were on average 1.5699,43.23%, and 0.5699, respectively. 'Zigonglingguan' was the highest, and A, P and Ho were 1.8889, 66.67%, and 0.8889, respectively, while 'Fenziguan', 'Fenguantuogui' and 'X16' had the lowest genetic variation and A, P and Ho were 1.3000, 25.00%, 0.3000, respectively. The UPGMA of these cultivars in D. grandiflorum showed that they were clustered together. The big-headed chrysanthemum cultivars possessed the similar genetic characteristic, and so did the small-headed ones, and the ones with anemone petals clustered alone. 70.37% cultivars of the big-headed chrysanthemum which had the same A, P and Ho were clustered together, and so did 87.18% cultivars of the small-headed ones. The clutivals with anemone petal were clustered solely.4. The mean heterozygosity (Ho) observed among 12 populations of D. indicum (Lao shan yeju, Hangzhou yeju, Lishui yeju ,Yizheng yeju, Shennongjia yeju, Huangshan yeju, Lushan yeju, Guizhou yeju, Taishan yeju, Chengdufengxia yeju, He'nan yeju, Nanjing yeju) ranged from 0.1667 to 0.7500. The genetic variation of Nanjingyeju (D. indicum) was the highest, and that of He'nanyeju was the lowest in the populations.5. The genetic variation of materials used in the study was very wide and the ornamental cultivars had the highest genetic variation compared with the others. A, P, He and I in the ornamental cultivars were 1.6544,91.67%, 0.3721 and 0.5257, respectively, while the wild species had the lowest genetic variation. The cultivars that can be clustered together possessed the similar genetic characteristics. Both the UPGMA and the genetic diversity dindex showed that the ornanmental cultivars evolved from the edible ones, the edible ones from the medicinal ones.6. The genetic diversity of 27 materials (Laoshanyeju, Hangzhouyeju, Lishuiyeju, Yizhengyeju, Shennongjiayeju, Huangshanyeju, Lushanyeju, Guizhouyeju, Taishanyeju, Chengdufengxiayeju, He'nanyeju, Nanjingyeju, D.zawadskii, D.chanetii, D.lavandulifolium, D.dichrum, D.nankingense, Tianzhushanmaohuaju, Funiushanmaohuaju, and 8 cultivars of Dendranthema×grandiflorum thar are 'Hangbaiju', 'Gongju', 'Chuju',' Yuji', 'Shanhualanman', 'Lüyu', 'Jinlongtengfei' and 'Zuihuatao') was researched. Nei's genetic identity of the materials was between 0.4616 and 0.8605, and the average genetic distance was 0.4517. Nei's genetic identity between D. grandiflorum and D. indicum was 0.8605, which showed that the two species had the nearest relationship and D. indicum was probably one of the original species of D. grandiflorum.7. 'Ranshuijintao', 'Fenzhuqiuyi', 'Jinlingzhiguang' and 'Jinlingchunse' had the specifical band (the band F of POD-3), 'Liishuiqingshan' and 'Mulanhuanzhuang' had the specifical band (the band O of EST-6), while the edibe cultivars 'Baoxintangyijin' and 'Jingxingxiying' had the specifical band (the band E of POD-2), which could offer the biology chemistry evidence for protecting the new cultivars in D. grandiflorum.