广西境内马褂木天然群体遗传多样性的 ISSR 分析.

In order to understand the genetic diversity and distribution model of Liriodendron chinense natural population in Guangxi Zhuang Autonomous Region, the genetic diversity and structure of six natural populations were analyzed by using ten ISSR markers. The results showed that there were abundant genetic diversity in six Liriodendron chinense natural populations. The average (or total) effective number of alleles (Ne), Nei's gene diversity (H) and Shannon information index (I) of six populations were 1.454 1 (1.633 7), 0.257 6 (0.363 3) and 0.378 6 (0.529 3). A limited gene flow (Nm=1.218 4) resulted in a high genetic differentiation (Gst=0.291 0) among populations. The six populations were divided into two groups depending on cluster analysis (UPGMA method). One group (west group) contains the populations near the west (RS-A, HJ and LY) and the other (east group) included the populations near the east (QZ, ZY and RS-L). The east group had a lower genetic diversity and higher differentiation than the west one, which probably implied that populations in east group were strongly disturbed by human activities. Mantel test (R=0.545, P=0.041) displayed a significant isolation by distance model among populations, which also implied that habitat fragmentation due to human activities was an important factor for a highly genetic differentiation among populations. In the light of abundant genetic diversity and highly genetic differentiation on L. chinense populations in Guangxi, not only in situ conservation for the populations with abundant genetic diversity (e.g. RS-A, HJ) is critical, but also ex situ conservation by seeds or cuttings collecting for all populations is also essential for further breeding and propagation. [ABSTRACT FROM AUTHOR]