Determination of genetic relationships between evergreen azalea cultivars in China using AFLP markers

Evergreen azaleas are among the most important ornamental shrubs in China. Today, there are probably over 300 cultivars preserved in different nurseries, but with little information available on the cultivar itself or relationships between cultivars. Amplified fragment length polymorphism (AFLP) markers were employed to determine the genetic relationships between evergreen azalea cultivars in China. One hundred and thirty genotypes collected from gardens and nurseries, including cultivars classified in the groups East, West, Hairy, and Summer, unknown cultivars, and close species, were analyzed using three primer pairs. A total of 408 polymorphic fragments were generated by AFLP reactions with an average of 136 fragments per primer pair. The average values of expected heterozygosity and Shannon's information index were 0.3395 and 0.5153, respectively. Genetic similarities were generated based on Dice coefficients, used to construct a neighbor joining tree, and bootstrapped for 100 replicates in Treecon V1.3b. Principal coordinate analysis (PCO) was performed based on Dice distances using NTSYS-pc software. The AFLP technique was useful for analyzing genetic diversity in evergreen azaleas. Cluster analysis revealed that cultivars in the West and Summer groups were quite distinct from other groups in the four-group classification system and that the East and Hairy groups should be redefined.