An AFLP analysis of genetic diversity and structure of Caragana microphylla populations in Inner Mongolia steppe, China

Genetic diversity and structure of five natural populations of Caragana microphylla from the Inner Mongolia steppe were estimated using AFLP markers. Five pairs of primers generated a total of 312 bands among 90 individuals, with percentage of polymorphic bands (PPB) being 63% at the population level and 76% at the species level, respectively. The genetic diversity within populations was correlated significantly with the soil N:P ratio. AMOVA analysis revealed high genetic variations within populations (95.5%). The estimated number of migrants per generation (Nm) was 10.72, indicating a high level of gene flow among populations. There was no significant correlation (r = 0.36) between genetic distance and geographical distance. These results were discussed in terms of eco-geographical variations among populations, together with the life history traits and breeding system of the species. The knowledge obtained may have important implications for better conservation and wise use of the vegetation dominate by C. microphylla.