This study looked at the differences among 297 samples of cannabis flower to determine if there was any correlation between Indica or Sativa labeling and genetics and terpene profiles. It was published in October 2021 as a Brief Communication in Nature Plants.
They found that the labels Indica or Sativa were not really correlated to genetic origin or metabolomic (biochemical component) variation. There was weak correlation with a few terpenes (less than 20% of the variation explained), with Myrcene weakly correlated with Indica labels and only bergamotene and farnesene weakly correlated with with Sativa Labels (11% variation explained).
In the data analysis world, 11% or 20% explanation of variation means they aren't REALLY correlated. They also found different flower samples with the same cultivar name that had very few genetic or biochemical commonalities.
Thus, we see again that patients and consumers need to look beyond any implied consistency of label names, and pay more attention to the lab tests and individual terpene and cannabinoid content of each product they consider. If lab tests with individual terpene amounts are not available BEFORE a product is purchased, we recommend considering another product.
Here are a few quotes from the article:
there is evidence to suggest that a cultivar’s terpene profile affects its psychoactive properties
Sativa–Indica labels thus do not accurately reflect genetic relatedness, which is consistent with previous work
In addition, we determined that pairs of samples with identical cultivar names (for example, OG Kush) were often as genetically and chemically distant from each other as pairs of samples with different names