Genetic diversity analysis of black locust (Robinia pseudoacacia L.) distributed in China based on allozyme markers approach

Using starch gel and polyacrylamide gel electrophoresis, the genetic diversity of 19 populations of black locust (Robinia pseudoacacia L.) distributed in China has been evaluated based on seven allozyme systems. Among the 14 enzyme loci studied, 12 of them showed polymorphic, giving a total of 40 alleles. The average allelic number (A) and the average effective allelic number (Ae) were 3.004 and 2.178, whereas the average of expected heterozygosity (He) and the observed heterozygosity (Ho) were 0.525 and 0.440, respectively. The total genetic differentiation (H _T ) in the 19 populations tested was 0.536, including 0.515 within population (H _S ) and 0.021 among populations (D _ST ). The mean coefficient of genetic differentiation (G _ST ) was 0.038, indicating that 3.8% of genetic differentiation was resulted from the populations, and the rest from those within the population. The genetic distance among the 19 populations was small, ranging from 0.015 to 0.065. Cluster analysis based on AVERAGE showed that populations with closer geographical distribution had higher genetic similarity than that in populations with far away distribution. There was no evident geographic differentiation pattern in Chinese black locust populations at a biochemical level.