Genetic similarity of natural populations and plantations of Pinus roxburghii Sarg. in Nepal

? Genetic structures of five population pairs each consisting of one natural population and one neighbouring plantation of Pinus roxburghii Sarg. in Nepal were assessed using nuclear (nSSRs) and chloroplast microsatellite loci (cpSSRs).

? The mean number of alleles at nSSRs loci in natural populations was 5.0 compared to 4.93 in plantations while the average observed heterozygosities were the same in both groups (H ₀ = 0.50). Most of the alleles were common to all the populations, indicating that the populations correspond to a single genetic entity. Similarly forty-seven haplotypes were observed in natural populations compared to fifty haplotypes in plantations. Mean haplotype diversities of natural populations (0.953) and plantations (0.955) were very similar. Genetic diversity of Pinus roxburghii was relatively high with low or no evidence of inbreeding while genetic differentiation among all populations was very low (about 1%).

? The very low differentiation among natural populations indicates efficient long-distance gene flow among populations resulting in homogeneous genetic structures at least at selectively neutral loci. Even though the harvest and production of seeds and seedlings was largely uncontrolled, genetic structures of most plantations show no signs of reduced variation, inbreeding or other negative effects compromising the adaptedness or adaptability of planted forests.