Cannabis Indica and Cannabis Sativa are the two main varieties of the cannabis plant used as medicine. There are many original landrace genetics of both varieties that come from many parts of the world. Within each of those varieties there are a huge number of individual strains, each with a different cannabinoid profile and medicinal effect.
As Indica strains have more chlorophyll than Sativa strains they grow and mature faster. Cross breeding Indicas with Sativas or a combination thereof creates hybrids. The resulting hybrid strains will grow, mature and differ medically in relationship to the indica/sativa percentages each phenotype contains.
The benefit of hybridization is that the breeder can attempt to create strains that are profiled to grower and patient needs. In today’s market hybrid strains dominate the market, as most strains have been crossed at one time or another.