An international team of scientists have found in a new study that the Cannabis plant was first domesticated in northwest China about 12,000 years ago. Scientists analysed 110 different genomes of marijuana from plants all over the world to trace its origin.
“It confirms it is one of the oldest cultivated plants,” Luca Fumagalli, one of the authors of the study, told New Scientist. According to Fumagalli, the plant was probably used as a multipurpose herb even at that time, and its uses could be food, fibre, oil as well as medical and recreational purposes. The research was published on July 16 in Science Advances.
The research also suggests that breeding different strains, well suited according to either drug or fibre production, only began about 4000 years ago.
Scientists took the genetic repository of the plant species’ group and sorted it into four groups — hemp (cultivated for fibre) varieties, cultivated drug-type cannabis, basal and naturally cultivated varieties, and feral drug-type cannabis. The extensive repository was made by combining 82 new genomes and 28 genomes that were already available publicly.
Scientists claim that they have uncovered the time and place of the geographic origin of the plant along with its genetic lineage. Their research also supports the idea of cannabis being a single species that the much-debated proposition that it is a group of three species names - Cannabis sativa, Cannabis indica, and Cannabis ruderalis. According to scientists, Cannabis indica, and Cannabis ruderalis are actually Cannabis sativa.
The researchers’ team also revealed many changes that the plant has undergone because of the selective breeding done by farmers. For example, if cannabis is grown for the purpose of fibre production, farmers prefer less branching hence breed the mutations that branch less. This selectivity gives rise to such mutations, and the other variants with branching die down. On the other hand, cultivation for its recreational drug use requires branched mutations that have more flowers, and hence more psychoactive drug content.
Cultivation of cannabis is illegal in India except when it is being used for industrial production (of mainly hemp fibre) or scientific research use.