Study On Genetic Diversity Of Caragana Microphylla Lam. In Inner Mongolia Central Region

Caragana microphylla Lam.is an important species in the semi-arid,drought and desert regions.It has a potential development in North China where there are rich wildlife resources.The experiment is based on a thorough investigation on the ecological distribution of C.microphylla Lam.,choosing C.microphylla Lam.from seven regions in central Inner Mongolia.30 samples from each region are chosen as the experimental material in order to research systematicly on the genetic foundation and variation of their germplasm. Meanwhile,their genetic diversity is revealed by systematic studies on different levels of morphology and DNA molecules.It is very helpful to provide theory for effective protection and development of wild germplasm resources as well as construction of core germplasm.Furtherly it lays a foundation for selecting and exploiting excellent Caragana breed.The main research results are as following:1.Phenotypic diversity of the findings:Eleven phenotypic traits of C.microphylla Lam.among or within are discussed in analyzing characters such as apical leaves,pods and seed.Analysis of variance for all characters are marked(P<0.01) or extremely marked(P<0.001),with large coefficient of variation,from 3.34%～31.72%.The average is 14.74%.The eleven phenotypic differentiation(Vst =16.9%at variance components;16.3%,according to the diversity index) shows that the variation within the population(83.1%) is slightly higher than that among others populations.In general,the phenotypic variation of C.microphylla Lam.in the central Inner Mongolia is different,in turn as Xiwuqi >Zhengxiangbaiqi>Siziwangqi >Chaha'eryouyihouqi > Xianghuangqi > Huade > Duolun in the relative analysis of the eleven phenotypic traits,there are marked or extremely marked difference among most traits;in the partial correlative analysis of geographically ecological genes,differences of phenotypic traits are highly related to geographically ecological genes.The result from the main components shows that cumulative contributions' rate of 1000-seed weight,pod length,pod stipule length and articulation length reach 94.32 percent.It is the main source for the phenotypical variation according to the PCA;Based on the cluster analysis,the seven C.microphylla Lain.populations can be divided into three categories by phenotypic traits,the correlation between phenotypic Continental distance and geographical distance is not very close according to Mantel's test. 2.ISSR molecular marker research findings:C.microphylla Lam.'s DNA of high quality is distilled by SDS method,which accords with ISSR analysis.Meanwhile a good ISSR reaction system of C.microphylla Lam.is established:PCR is 25ul,with75ngDNA,0.6umol / L primer,0.4 mmol / L dNTPs, 2.5mmol / L Mg²⁺,1.5U Taq enzyme,10×PCRbuffer(10mmol / L Tris-HCl pH8.3, 50mmol / L KCl,0.001%gelatin),and response procedures:pre-5 rain denaturation at 94℃,and then 45 cycles 94℃45s,and 53℃1min,72℃1.5min,the final extension of 10 min at 72℃,after 4℃.The results of ISSR analysis shows that the genetic diversity among 7 C.microphylla Lam.Accessions in population is tested by ISSR,168 wild materials are amplified by 18 ISSR primers,as a result 269 bands are gained.Each primer generated 14.94 polymorphic bands,From280bp to 1500bp,177(66.27%) bands are found to be polymorphic.Higher genetic diversity is both observed at species level(H = 0.2849,I = 0.4208) and population level(H = 0.2280,I = 0.3413).Its correlation with genetic diversity parameters and geographically ecological genes is not so close.Based on genetic differentiation(Gst) 19.98 percent,most of genetic variation of C.microphylla Lam.is within population(80.02%).The gene among populations Nm=2.0025.Base on the cluster analysis shows that seven C.microphylla Lam.populations can be divided into three categories,Mantel's test found that the correlation between genetic distance and geographical distance correlation is not very close.3.The data couples on Phenotypic and molecular levels of C.microphylla Lam.,which is well coincided and suggests C.microphylla Lam.has a higher level of genetic diversity.