Pot Purveyors Seek Genetic Tweaks as Legal Cannabis Grows

A good marijuana plant used to be one that grew well indoors and generated the best high for users.

But with more states and Canada legalizing marijuana for medical and recreational use, scientists and plant breeders are looking to the plant’s genetic map to create pot that produces more health benefits and requires fewer pesticides to grow.

At least three projects are in the late stages of mapping the cannabis plant genome. Tying specific genes to plant characteristics could allow growers to emphasize compounds that manage pain, control epileptic seizures, and regulate moods while reducing THC, the substance that gets ...