3.1 Polymorphism of AFLP markers
The eight primer pairs yielded 1728 clearly identifiable amplified bands, of which 1654 (95.72%) were polymorphic (Table 2). Different primers yielded different numbers of bands ranging from 214 (E -ACG/M -CTC) to 199 (E -AGC/M -CTG andE -AAG/M -CAC) with an average of 207. The highest rate of polymorphism for an individual primer was 99.07%, and the lowest was 92.13%. Overall, these eight primers showed high levels of polymorphism among individuals of P. villosa .
The indices, N a, N e, h , and I were important indicators of genetic diversity of populations. According to the genetic diversity index of eight primer pairs, the indices of N a,N e, h and I ranged from 1.9950 to 2.0000 with an average of 1.9994, 1.2898 to 1.3445 with an average of 1.3229, 0.1926 to 0.2131 with an average of 0.2056, and 0.3183 to 0.3379 with an average of 0.3316, respectively. Overall, these indices showed the highest genetic diversity for the primer pair of E -AGG/M -CAC, while the lowest was for E -ACT/M -CTT. In general, each of eight primer pairs appeared to facilitate a robust assessment of genetic diversity in P. villosa .