Roasted meat with gourd (commonly called night flowering) is a delicious dish in early summer in southern China, but sometimes it is bitter when it comes to gourd, and even the meat is too bitter to eat. In the north, people like to eat cucumber with crispy meat and juicy juice. It has a special flavor when eaten raw, but sometimes it is so bitter that it makes people's tongue numb. Why are gourd and cucumber bitter? People who grow melons often guess that melons and vines have been trampled by their feet; Some people think that there is too much fertilization when planting melons, and everyone has different opinions.

Gourd and cucumber are cucurbitaceae plants, and their ancestors "wild species" contain bitter substance-glucoside. In the long-term selection and cultivation, the wild species containing bitter substances were gradually cultivated into cultivated varieties without bitter substances, and now they have become soft and tender gourd and crispy cucumber. However, in the biological world, there are often individual plants that show the characteristics of "ancestors", and there are "bitter gourd" or "bitter cucumber" plants, and the melons produced by this bitter plant are all "bitter gourd" or "bitter cucumber". This situation is called "atavism". In other words, their bitterness was passed down from their ancestors.

We can do an experiment. Leave the bitter melon seeds of the "atavism" plants, and plant them the next year, and the gourd or cucumber will still be bitter. If the pollen of bitter melon is given to the pistil of non-bitter melon, or the pollen of non-bitter melon is given to the pistil of bitter melon, their respective seeds will grow bitter gourd or cucumber after sowing the next year. From this experiment, we can know that the bitterness of gourd and cucumber is hereditary and controlled by a pair of dominant genes.

Knowing the main causes of bitter melon, we can take measures to prevent it. First of all, the bitter gourd and cucumber varieties should be eliminated, and this work should be started when the seeds are selected. Secondly, improving cultivation management, rational fertilization and irrigation, and promoting the normal growth of plants are also necessary measures to prevent bitter melons.