Chrysanthemum is native to my country and is one of my country’s traditional and precious flowers. Its ancestor is a small yellow flower. After three thousand years of continuous natural selection and artificial cultivation, it has developed into more than 4,000 varieties today. Chrysanthemums have many changes in leaf shape, flower shape and color, ranking first among flowers. In daily life, colorful and varied chrysanthemums bring people beautiful enjoyment.

Chrysanthemums not only provide people with beautiful enjoyment, but some chrysanthemums also have very important practical value. For example, Hangju in Zhejiang is a good refreshing drink; Chuju and Haoju in Anhui are good for clearing away heat. , detoxifying traditional Chinese medicine; pyrethrum is a well-known natural pesticide. In addition, chrysanthemums are not afraid of smoke pollution and can absorb gases in the air that are toxic to humans, animals and plants, such as sulfur dioxide, hydrogen fluoride, etc. Chrysanthemums play a role in purifying the air and protecting the environment.

The variety of chrysanthemums in nature is mainly due to changes in the natural environment and methods of artificial hybridization, domestication and mutagenesis. First of all, in nature, due to changes in climate and soil environmental conditions, the original flower color changes and forms a new flower color. People select it and preserve it through asexual reproduction. This is what people call "budding" . Second, sexual hybridization involves crossing two varieties of different colors to produce a third flower color. There are conscious hybridizations by people, and there are hybridizations between bees, butterflies and wind pollination. Third, use new physical and chemical techniques to cause "mutations" in chrysanthemums, such as using rays, Y-rays and neutron rays to treat chrysanthemum seeds or branches. This artificial "mutagenesis" can create new varieties more quickly. Fourth, grafting can also be used to graft branches of many different varieties of chrysanthemums onto one chrysanthemum, so that one chrysanthemum becomes multiple colors.

So far, the methods for increasing chrysanthemum flower color varieties generally include the above methods. However, are there other more ideal breeding methods such as the application of plant growth regulators? At the same time, no matter which method is used to select chrysanthemum varieties, people still cannot accurately select the desired flower shape and color, which in a sense is arbitrary and blind. A series of issues such as the genetic mechanism of chrysanthemum still need further research.