Seedling barrier is an obstacle form of product trade barrier. At present, the trade barriers of mushroom products in China are caused by scientific and technological factors, political factors and human factors. The product trade barrier set up on the grounds of protecting the right to use seedlings and the right to harvest seedlings is called seedling barrier, which aims to protect the intellectual property rights of breeders and the interests of domestic growers. The main contents of the "seedling barrier" set by Japan in 2003 are:

(1) In order to protect intellectual property rights, domestic agricultural products sales and the interests of domestic mushroom producers, the Japanese parliament passed the Seedling Amendment on June, 2003, which extended the protection of the rights and interests of new plant variety breeders from the seedling stage to the harvest stage of planted products.

(2) The revised Japanese Tariff Amendment Act has been fully implemented since April 1 2004. According to this law, without approval, the customs has the right to refuse the entry of agricultural products produced abroad and sell them in Japan, and the fine can be increased from 3 million yen to 6,543.80 billion yen.