关键词: 七子花, 大小级种群, RAPD, 遗传多样性

Abstract:

Heptacodium miconioides collected from Tiantai Mountain of Zhejiang Province was divided into 4 populations according to the size class, namely big tree population, middle tree population, arboret population and young tree population. The genetic diversity within populations and genetic differentiation among 4 populations with different size class (45 samples) were analyzed and compared using random amplified polymorphic DNA (RAPD) technique. The results showed that 64 repeated loci were detected by using 12 random primers. The highest percentage of polymorphic loci was detected in big tree population. The middle tree population took second place and the arboret population took the third place. The lowest percentage of polymorphic loci was detected in young tree population. The highest genetic diversity estimated by Shannon index was revealed in big tree population. The secondary was middle tree population and the third was arboret population. The lowest genetic diversity was revealed in young tree population. 45.59% of genetic diversity was attributed to the differentiation among populations while 54.41% resided within populations. It suggested that the genetic differentiation might exist within and among populations with different size class, but the genetic differentiation within populations was higher than that among populations. The gene diversity estimated by Nei's index was consistent with that estimated by Shannon index and the genetic differentiation within populations was higher than that among populations. The gene differentiation coefficient among populations was 0.393 9. The genetic similarity between big tree population and middle tree population was the highest while that between big tree population and young tree population was the lowest. The clustering analysis was performed using the software POPGENE32 and the results showed that 4 populations with different size class could be divided into 2 clusters, namely cluster 1(big tree population and middle tree population) and cluster 2 (arboret population and young tree population). Furthermore, the two clusters gathered.

Key words: Hepatacodium miconioides, Populations with different size class, RAPD, Genetic diversity