RAPD AND SSR ANALYSIS OF GENETIC DIVERSITY OF NATURAL LARIX GMELINII POPULATIONS

We analyzed the genetic diversity of 270 individual samples from six natural Larix gmelinii populations, using 31 random amplified polymorphic DNA (RAPD) primers and 31 expressed sequence tag-simple sequence repeat (EST-SSR) primers. The following populations were sampled: Wuyiling (WYL), Ganhe (GH), Kuduer (KDE), Nenjiang (NJ), Moerdaoga (MEDG), and Aershan (AES), China. High genetic diversity was detected, with the greatest diversity observed in the KDE population. The results from both marker methods revealed that primarily within-population variation was observed. Using 31 RAPD primers, 244 loci were amplified and found to exhibit high polymorphism, with a percentage of polymorphic bands (PPB) equal to 97.13 %. The mean PPB for all six populations was 87.98%, with individual PPBs as follows: 88.11 % (NJ), 88.93% (GH), 89.34% (KDE), 87.70 % (WYL), 87.30 % (MEDG), and 86.48 % (AL'S). The PPBs for NJ, GH, and KDE were greater than the average, whereas those for WYL, MEDG, and AES were lower KDE, GH, and AES had a larger than the average values for Nei's genetic diversity index (H) and Shannon's diversity index (SI). From H, we estimated the coefficient of population differentiation (G(st')) as 0.1592, with a genetic distance ranging from 0.0415 to 0.1534. Using 31 SSR primers, we detected 64 alleles, with a PPB of 100 %. The mean observed heterozygosity (H-o) was 0.3087 (0.2616-0.3412) and the mean expected heterozygosity (H-e) was 0.4711 (0.4440-0.4832). The mean H-o calculated from H was 0.4658 (0.4440-0.4832). The highest H-e and H-o levels were found in the KDE population. G(st) estimated by Nei's index was 0.0624; the genetic distance was 0.0235-0.0992.