Turnip (Brassica campestris L.ssp. rapifera Matzg or Brassica syn. rapa L.ssp. rapifera), chromosome number 2n=2x=20, also known as campestris, round root, kamagu, Pancai, etc., are biennial herbaceous plants of the genus Brassica of the Brassicaceae family. The fat fleshy roots, crisp young leaves and plump flower sprouts are eaten as vegetables and are also good food for waste and livestock feed.

The fleshy root of the turnip is crisp, sweet, juicy and rich in nutrients. Each 100g of turnip contains 6.3g of carbohydrates, 1.4g of protein, 0.1g of fat, 0.9g of crude fiber, 35mg of vitamin C, 0.04mg of riboflavin, 0.07mg of thiamine, 0.3mg of niacin, 41mg of calcium, and 0.5mg of iron. , Phosphorus 31mg ("Food Composition List", 1981). According to Tao Yueliang (2002) and others, the contents of soluble sugar, free amino acids, soluble solids, protein, vitamin C, crude fiber, carotene, riboflavin, calcium and iron in turnip fleshy root (Wenzhou Pancai) are respectively 1.30 times, 1.20 times, 1.61 times, 2.14 times, 1.93 times, 0.68 times, 1.24 times, 3.43 times, 2.09 times and 0.97 times of radish.

Turnip also has good health care functions. Farmers and herdsmen in Taxkorgan Tajik Autonomous County, Xinjiang have always called turnip "little ginseng". Its fleshy roots have the effects of nourishing vitality, improving eyesight, clearing the lungs and relieving coughs, easing urination, and alleviating morning sickness. In addition, turnip juice also has obvious protective and repair functions against radiation damage, and can significantly inhibit the growth of cancer cells (Qian Xiaowei, 2003).

Turnip has been eaten in China as early as 2,600 years ago. It was domesticated and cultivated during the Qin and Han Dynasties. By the Northern and Southern Dynasties, it had developed into the most important root vegetable crop in the north. But in the Tang Dynasty, with the rise of radish, this pattern changed; by the Ming Dynasty, radish had formed various types, gradually replacing turnips and becoming the most important root vegetable crop in the south and north. On the contrary, turnips gradually decreased and even retreated to the mountains and fields (Ye Jingyuan, 1995).

At present, the cultivated area of ??turnip in various parts of China is very small. It is mainly distributed in the semi-agricultural and semi-pastoral alpine zones in the northwest and southwest, some mountainous and hilly areas in North China, southern Zhejiang and northeastern Fujian. What is gratifying is that in recent years, turnips from Wenzhou, Zhejiang have become popular again and are exported to Southeast Asia, becoming one of the leading vegetables for local exports to earn foreign exchange. In addition, small turnips imported from Japan have also been introduced in various parts of the country due to their early maturity (35-60 days of growth period), beautiful appearance (round or flat, red or white, smooth skin, small tail root), and tender meat. , its fleshy roots are often cut into shreds and eaten cold, as salads, stir-fried or pickled.

China is rich in turnip germplasm resources. According to the "Catalogue of Chinese Vegetable Variety Resources" (1991, 1998), there are 92 copies.