Résumé
To further study and fully exploit the medicinal plant Sophora alopecuroides, the molecular markers related with the phenotypic traits of alkaloid content in S. alopecuroides should be detected. In this study, SSR molecular markers were used to analyze the genetic diversity and genetic structure of 23 S. alopecuroides populations, in combination with the association analysis between molecular markers and the alkaloid contents. The results showed that P, H, I, G_(st) and N_m values were 40.10%, 0.335 3, 0.504 5, 0.433 7 and 0.625 9 respectively, in 23 S. alopecuroides populations. This indicated that there was less gene exchange and higher genetic differentiation among different S. alopecuroides populations. The results of SSR unweighted pair-group method with arithmetic means(UPGMA) cluster showed that the S. alopecuroides populations relationship from Xinjiang was far from the populations of other regions, but the populations of S. alopecuroides from Gansu, Inner Mongolia and Qinghai were closely relevant to those from Ningxia. The 23 populations were further divided into 2 genetic subpopulations by the population structure analysis. Through association analysis, a total of 26 loci in 13 SSR markers were found to be significantly associated(P<0.005)with the content of MA, OMA, SC and OSC, and the rate of explanation on the phenotype variance of related markers ranged from 36.45% to 77.93%. Among the locus, 1 each were related with MA and OSC content at interpretation rate reached as high as 50% with high threshold(P<0.000 1). These results could provide support for the discovery of important genes in the alkaloid biosynthetic and metabolic pathway of S. alopecuroides.