Studies On The Genetic Diversity Of Rare And Endangered Shrub Reaumuria Trigyna In The Western Ordos

RAPD and ISSR this study has been used to performed to reveal the population genetic diversity of Reaumuria.trigyna on the west Ordos region in Inner Mongolia. A total of 118 loci (including 105 polymorphic loci) were amplified using 18 random primers for RAPD and a total of 114 loci (including 99 polymorphic loci) were amplified using 14 primers for ISSR.The average percentage of polymorphic bands (PPB) are 88.98% for RAPD and 86.84% for ISSR respectively. High level genetic diversity of the endangered shrub R. trigyna was detected by the two markers. Nei's gene diversity showed that there were major genetic variations within populations. Genetic variations within populations were 85.86% by RAPD and 89.36% by ISSR. There was strong gene flow among populations(Nm was 4.3159 by RAPD and 4.7299 by ISSR), so genetic variations was low among populations. The results showed endangered plants was not necessary to displayed lower level of genetic variation.The genetic diversity of R. trigyna at specie level (HO=0.4966, HE=0.3303) and population level (HO=0.4228, HE=0.2853) revealed by RAPD are all higher than those by ISSR (specie level: HO=0.4688, HE=0.3084; population level: HO=0.4111, HE=0.2753). Therefore, RAPD molecular markers are more suited than ISSR molecular markers when test the genetic diversity of R. trigyna populations to determine the genetic relationship of populations or individuals. Correlation coefficient between genetic distance from RAPD and from ISSR is P=0.814>0.05.The correlation analysis showed that there was no significant correlation between genetic diversity(PPB, HO, HE) and ecological factors (altitude and soil) of five R. trigyna populations. The result also showed there was no significant relativity between genetic distance and geographic distance of R. trigyna (P=0.687>0.05).We compared the results and found there was obvious difference between two markers, RAPD markers revealed higher genetic diversity and differentiation than ISSR markers in terms of polymorphic loci percentage, Shannon's information index and Nei's gene diversity index.