Studies On The Problem Of Origin Of Chinese Garden Chrysanthemum

Chinese garden chrysanthemum belongs to the composite family.It is a traditional famous flower in China.It has been developed into one of the world wide plants, having the most abundant cultivars.The problem on the origin of garden chrysanthemum has been a question receiving more attention by horticulturists and botanists in the world in recent years.This study collected chrysanthemum germplasm resources and established chrysanthemum gene pool in Beijing on the basis of surveying and investigation.The establishment of germplasm garden creates appropriate conditions for the study on the origin of the garden chrysanthemum(some experiments such as introduction, cultivation,breeding,interspecific hybridization,ISSR molecular marker).Major stems of the study consist of surveying and collection of germplasm resources include Chinese medicinal chrysanthemum,an ancient group of chrysanthemum,in the narrow sense of the word chrysanthemum spp.and its' closest affinity genus that have weathered the lighter erosion of the varieties.They are all used as the experimental materials,by different techniques for finding the new evidence to the origin of Chinese garden chrysanthemum.Through visiting experts,information,access to specimens,and on-the-spot investigations 25 representative spots of 11 provinces or cities,such an Anhui,Henan, Hubei and other provinces,14 types of medicinal chrysanthemum cultivars, multi-chrysanthemum species of wild plants,and 4 Chrysanthemum vestitum-indicum natural hybrids were collected.Comprehensive and systematic collection of chrysanthemum of China has been preserved and a germplasm resource garden has been established in Beijing Forestry University.These germplasm resources conserved effectively and used as basic materials for resolving the problem of origin of chrysanthemum research.At the same time the biological characters of some species and varieties of the genus Chrysanthemum have been studied in order to lay the foundation for Chrysanthemum breeding.It is about 4 years work for distant hybridization of chrysanthemum,and a total of 47 hybridization combinations,3225 seeds,675 hybrid seedlings,30 flowering variation seedlings have been achieved.It is easier for the success to obtain hybrid of Chrysanthemum vestitum and C.indicum,C.vestitum and C.zawadskii,C.vestitum and C.lavandulifolium.Their seeds can be achieved easier too.The No.one generation has larger variation.Many characters such as inflorescence,flower color, leaf type and so on are almost like those of mums.No.two generation has greater variation than No.one after natural pollination.They are almost entirely mums.As to flower color interitance,the result,did not in favor of the view of inclining to maternal heredity,but heritability of the red flower color is stronger than that of yellow one,and white and yellow are the basis of the hybrid parents color.ISSR-PCR molecular systematic research used by 86 chrysanthemum plants was made and analyzed.The following conclusions were gained that:finalize the 10 primers that are clear and abundant polymorphism,with them 86 materials were used to study the genetic diversity of chrysanthemum.A total of 150 ISSR bands statistics can be amplified.The ratio of polymorphism(PPB) is as high as 99.3 percent on the test for the genetic polymorphism.This shows that the genotypes of chrysanthemum are very rich.The description of the genus Chrysanthemum is divergent;From cluster tree analysis of ISSR-PCR,it is obtained that the C.vestitum and ornamental chrysanthemum,medical chrysanthemum have most closely genetic affinity,followed by C.vestitum at Yichang city,C.zawadskii,C.nankingense;The evolution of garden chrysanthemum may be mainly in one ways:Wild Chrysanthemum to Medicinal Chrysanthemum to Ornamental Chrysanthemum.Researches on the origin of Chinese garden chrysanthemum have sustained for nearly half a century(from 1961).All results were made systematically and summarily for leading to introduction and domestication of tests,taking into account macro-morphology,Microscopic cytology,Palynology,Isozyme,ITS sequencing, DNA molecular markers,artificial hybridization,wild resources survey,historical analysis,etc..A conclusion was reached that:origin of Chinese Garden Chrysanthemum(Tao Yuan-ming times-the original chrysanthemum) in China,mainly emerged in the middle reaches of Yangtze River(Hubei,Anhui,Henan),the wild species of natural interspecific hybridization was cultivated into hybrid cultigen complex,after repeated long-term artificial selection of some type of special variation. The main parents of the hybrid cultigen complex might be C.vestitum and C.indicum, followed by C.zawadskii,C.nankingense,C.lavandulifolium,C.lavandulifolium var. aromaticum,C.dichrum and so on.They participated in the evolution of Chinese Garden Chrysanthemum by pollen,infiltrated germplasm to enhance the diversification of the gene.Crossing of natural interspecific hybridization(including hybrids),delicate cultivation and selection continuous of hybrid have played crucial role.