China is aiming to have 6.66 million hectares on which to grow potatoes by 2020, as the crop is set to become the nation's fourth food staple after rice, wheat and corn, according to a guideline released on Tuesday.

The guideline on developing the potato industry, released by the Ministry of Agriculture, also states that the country will encourage consumption of tomatoes as a staple food.

It says that authorities will ensure that 30 percent of the potatoes cultivated are varieties that are good for the production of food staples. The consumption of potatoes for food-staple purposes will comprise 30 percent of total potato consumption.

China is the world's largest producer and consumer of potatoes, and also had 5.5 million hectares on which to grow tomatoes in 2014, the ministry said in a statement on its website.

However, the annual consumption of potatoes per capita is only 41.2 kilograms, far below that of the European Union and the United States, the ministry said.

The guideline states that the country will select a number of potato varieties that are good for processing food staples, develop production bases for tomatoes as raw materials, and develop leading enterprises to process potatoes as food-staple products.

Zeng Yande, head of the ministry's Department of Crop Production, said in a news release on Tuesday that potatoes have been included in the country's food staples as China faces mounting pressure to upgrade the agricultural sector.