Establishment Of GISH Technique In Chinese Jujube And Study On The Origin Of ’Zanhuangdazao’

‘Zanhuangdazao’ is natural triploid Chinese jujube cultivars, it shows the advantageof polyploidy, such as well-adapted, huge fruit, sweet taste, rich in nutrient. The origin ofnatural triploid is still unclear, Polyploid breeding is one of the effective ways ofgermplasm innovation, GISH and45S rDNA or5S rDNA is advantageous to explore theorigin of polyploidy and genomic homology comparison. The experiment on the basis ofreference to other crops GISH process, a genomic in situ hybridization (GISH) techniquewas established in Ziziphus Mill., to investigate the origin of triploid ‘Zanhuangdazao’.These experiments may bring data for cytological studies of jujube, polyploid cultivars,and recognition of chromosome. The main results were as follows:1. Through optimization of the wall degradation hypotomic method of chromosome,probe preparation and chromosome DAPI concentration, a genomic in situ hybridization(GISH) technique was established in Ziziphus Mill., and the genomic homology betweenjujube and wild jujube was checked by this technique. GISH of the wild jujube withgenomic DNA probe of Chinese jujube ‘Fupingdazao’ on metaphase and GISH of‘Fupingdazao’ with genomic DNA probe of wild jujube on metaphase, and GISH ofChinese jujube ‘Zanhuangdazao’ with genomic DNA probe of ‘Fupingdazao’ or wildjujube on metaphase showed very strong hybridization signals in all chromosomes and thesignals distributed on the whole chromosoles. The results showed that Chinese jujube andwild jujube had high genomic homology, the new evidence was provided to confirm thejujube originated from wild jujube and they belonged to the same species.‘Zanhuangdazao’ should be an autotriploid.2. Physical mapping of5S rDNA and45S rDNA on metaphase chromosomes inChinese jujube and wild jujube by FISH(1) Physical locations of5S rDNA on mitotic metaphase chromosomes of threecultivars or types in Chinese jujube and wild jujube were carried on by means offluorescence in situ hybridization. The results showed that the5S rDNA sites on mitoticmetaphase chromosomes of ‘Fupingdazao’,‘wild jujube’,‘Zanhuangdazao’ were6,4and4respectively;‘Fupingdazao’ of5S rDNA hybridization signals were locatedchromosomes1,2,6and7;‘wild jujube’ of5S rDNA hybridization signals were located chromosomes1and3;‘Zanhuangdazao’ of5S rDNA hybridization signals were locatedchromosomes2and6; Among these cutivars or types, the numbers and located regions of5S rDNA sites were different.(2) Physical locations of45S rDNA on mitotic metaphase chromosomes of fivecultivars or types in Chinese jujube and wild jujube were carried on by means offluorescence in situ hybridization. The results showed that the45S rDNA sites on mitoticmetaphase chromosomes of ‘Fupingdazao’,‘wildjujube’,‘Linglingzao’,‘Zanhuangdazao’,‘Pingguozao’ were4,4,2,5and5respectively;‘Fupingdazao’ of45SrDNA hybridization signals were located chromosomes1,3and12;‘wild jujube’ of45SrDNA hybridization signals were located chromosomes2and3;‘Linglingzao’ of45SrDNA hybridization signals were located chromosomes2;‘Zanhuangdazao’ of45S rDNAhybridization signals were located chromosomes1,3,5and12;‘Pingguozao’of45S rDNAhybridization signals were located chromosomes3,5,6and12.Among these cultivars ortypes, the numbers and located regions of45S rDNA sites were different. According to thelocated regions of signals on these cultivars or types, three types were detected: thecentromere region of long or short arms, pericentromeric regions, telomeric region in shortor long arms. The further demonstrate that the origin of ‘Zanhuangdazao’ may be relatedto ‘Fupingdazao’.3.‘Fupingdazao’,‘Linglingzao’ as blocking DNA,‘Linglingzao’,‘wildjujube’,‘Fupingdazao’ with genomic DNA probe of ‘Zanhuangdazao’ on metaphase. The resultsshowed that:‘Fupingdazao’ as blocking DNA,‘Linglingzao’ and ‘wild jujube’ withgenomic DNA,‘Zanhuangdazao’36chromosomes in24chromosomes were completelyblocked no hybridization signals and12chromosomes had hybridization signals;‘Linglingzao’ as blocking DNA,‘Fupingdazao’ with genomic DNA,‘Zanhuangdazao’36chromosomes in12chromosomes was completely blocked no hybridization signals and24chromosomes had hybridization signals. The further confirm that the origin of‘Zanhuangdazao’ was produced by hybridization with2n gamete of ‘Fupingdazao’ and ngamete of unknown Chinese jujube cultivars or wild jujube.