Today I bought a Pape citrus and tasted one that wasn't very sweet. The owner directly said, "These past two years, Pape citrus haven't been very sweet either. It's because they no longer use sweeteners," and he even used his uncle as an example. His uncle also grows Pape citrus and hasn't used any sweeteners in the past two years. He also mentioned that testing has become stricter, and fruits must have testing certificates. But I remember that adding sweeteners to fruits to accelerate sweetness seems to be a misconception, because it's costly and probably ineffective. But why would he explain it this way? It's a mystery.