SAN JUAN, Puerto Rico (AP) — Jesus Aponte pushes a door open to reveal hundreds of aromatic, spiky green plants, a crop that Puerto Rico hopes will help it ease a grinding economic crisis by generating millions in revenue and tens of thousands of jobs.

Aponte, a 29-year-old biologist and chemical engineer, had been thinking of joining the wave of young Puerto Rican professionals heading to the U.S. to seek work — an exodus that has aggravated the U.S. territory's woes. But then he saw the saw the island's medical marijuana industry start to expand, and found one of the rare new jobs opening up...