| Zanhuangdazao (Ziziphus jujuba Mill.) was known as a unique triploid cultivar with best quality. Studies on geographic distribution and genetic variation of Zanhuangdazao original forms could provide theoretic evidences for its utility and protection. By combing its geographic distribution with analysis of chromosome number, geographic distribution of Zanhuangdazao original forms was studied for the first time. Genetic diversity > genetic structure^ genetic relationships between populations ^ origin and evolution of Zanhuangdazao and its related populations was also analyzed by using RAPD(Random Amplified Polymorphic DNA) technique in the paper. Main results were as follows:1 .Chromosome number of 42 Zanhuangdazao forms was analyzed for the first time, which suggested that all Zanhuangdazao forms tested were triploid, that was, 2n=3x=36. Zanhuangdazao original forms distributed in Zanhuang county of Hebei province mainly, make Xiyangzcx Yuantou as the towns distributed denselly, next to which were Nanqinghes Chengguan> Xilongmem Zhanglengx Huangbeiping of Zanhuang county > Sucun of Yuanshi county ^ Xifucun of Gaoyi county and Xishu of Lincheng county.2.Optimum system of RAPD amplification for Chinese jujube and wild jujube was established. In 20ul reaction solution: Tris-HCl(pH8.3) lOOmmol ?L"',KC1 50 mmol -L"',Mg2+ 2.0 mmol -L"1; Tag DNA polymerase 1.2U; dNTPs 100 pi mol I/1; Primer 0.2 p mol ?L"1; Template 40~60ng. The amplified procedure was : Step 1: 94癈 3 min; Step 2: 94癈30s,36癈40s,72癈 lmin,40 cycles; Step 3:72"C5min.3. Total 22 primers, among which 20 were polymorphic between Zanhuangdazao forms ,were used in RAPD amplification of 50 Zanhuangdazao forn^ 26 wild jujube formsN 6 Chinese jujube cultivars or forms in or nearby Zanhuang county, one Dongzao and an unknown cultivar or form in garden of Agriculture university of Hebei. 284 loci were gained among which 261 loci were polymorphic. Average loci number amplified per primer and length of loci were 13 and 270bp~2500bp respectively.4.Total 19 forms had specific RAPD markers which was 22.6 percentage of the forms tested. Among the 19 forms , there were 14 wild jujube forms.S.The identification efficiency of 22 primers differed with each other. The identification efficiency of primer S12 was highest(59.5%), and then primer S27> S368, whose identification efficiency was 53.6% and 46.4% in order. All the 84 forms tested could be identified by using the three primers.6.Genetic diversity of Zanhuangdazao and its related populations was studied for the first time in several aspects, they were percentage polymorphic loci, gene heterozygosity, kinds and frequency of genotypes^ genetic distance within population.(1 percentage polymorphic loci: Percentage polymorphic loci ofZanhuangdazao(58%) was lower than that of wild jujube and 8 other Chinese jujube cultivars or forms by 31% and 8% respectively.(2)Gene heterozygosity: Gene heterozygosity of Zanhuangdazao population, wild jujube populations, other Chinese jujube cultivars or forms population was 0.105, 0.233 and 0.164 in order.(3)Kinds and frequency of genotypes: Genotypes kinds amplified among Zanhuangdazao forms was less than that of wild jujube except by primer S12^S27>S176. What's more, the distribution frequency of genotypes in former was also uneven.(4)Genetic distance within populations: Average genetic distance in Zanhuangdazao population was 0.087,which was less than that of Chinese jujube cultivars or forms population (0.181) and wild jujube population (0.254).7.Genetic structure of Zanhuangdazao and its related populations were studied for the first time. The main results were: DST value and GST (coefficient of gene differentiation) of 3 populations was 0.05 and 0.231 respectively, which indicated that 23.1% variation partitioned among populations. Nm |
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