Genetic Diversity, Genetic Erosion, Conservation of Genetic Resources, and Cultivation of Medicinal Plants

Abstract

Wild or cultivated plants used in traditional and modern medicines are categorized as medicinal plants (MPs). Out of over 70,000 MPs, 3000 are traded and 900 are cultivated. Fragmentation/loss of habitats, unsustainable harvests, excessive grazing, invasive species, pollution, and climate change are destroying genetic diversity. Regular use of MPs in modern medicines, consumer/industrial merchandises, and increasing popularity of complementary and alternate (CAM) therapies are expanding national/global trade inciting irrational wild collections beyond regeneration potential of wild populations consequently losing species and genetic diversity. Investigations on endangered species indicated frightening levels of genetic erosion and dwindling population densities/sizes below minimum viable limits. Only a small fraction of known MPs have been evaluated for their genetic diversity and genetic erosion. Morphoagronomic, biochemical and molecular marker, and enzyme studies on wild and cultivated genotypes, populations, species, and geographical regions revealed genetic diversity with varied levels of polymorphism (14–100 %), number of alleles (2–14/locus), observed (0.0–1.0) and expected (0.06–0.84) heterozygosities, Nei’s gene diversity (0.12–0.36), Shannon’s index (0.08–0.51), gene flow (0.22–4.69), genetic distances (0.02–0.54), and similarities (0.02–0.98). Recovery, conservation, and cultivation programs initiated by governments have slowed down genetic erosion. Cultivation helped in relieving harvest pressure on wild flora and in preserving genetic diversity of some species. Existence of large number of species, paucity of adequate research funds, loss/degradation of forests, ever increasing local/world demand, genetic resource utilization with benefit sharing, and patent conflicts are the concerns that need to be resolved for conserving genetic diversity and preventing genetic erosion.