When is the latest planting time for purple sweet potato?
Purple sweet potato is also known as black sweet potato, shao sweet potato, etc. The flesh is purple to deep purple. It is grown in Guangdong, Guangxi, Hunan, Hubei, Fujian, Sichuan, Yunnan, Guizhou, Shandong, Jiangxi, Shaanxi and other places in China. It has high edible value and is one of the main raw materials for anthocyanins. Now let us take a look at the planting time of purple sweet potato!
Planting time of purple sweet potato
The planting time of purple sweet potato is generally mid-February. When the temperature reaches about 15 degrees in mid-February, the roots can be taken out of the cellar for seedling raising. First make the seedbed, place the seeds horizontally in connected rows on the seedbed, with a row spacing of about 5 cm, cover with fine soil, moisten the soil with a sprayer, cover with plastic film, and then cover with an overhead film to preserve moisture and heat. When the sprouts grow to more than 20 cm, they can be cut and inserted into the field. Seed purple sweet potatoes are required to be harvested in mid to late October, while those for fresh eating are delayed until early November and must be completely harvested before frost. Before storage, clean the potato cellar, remove the surface soil and disinfect it. Before entering the cellar, sun-dry the purple sweet potatoes for 1-2 days so the wounds heal. During storage, pay attention to ventilation and humidity reduction in the early stage, and to heat and moisture preservation in the later stage.
Growing environment of purple sweet potato
Purple sweet potato likes a warm climate environment. The suitable growth temperature for stems and leaves is 18-25°C. Growth stops when the temperature is below 15°C. The most suitable soil temperature for root tuber growth is 22-24°C, and enlargement stops when the soil temperature is below 20°C. It is a short-day crop and needs sufficient light and high intensity. During the growth period, the suitable soil moisture is 60%-80% of the maximum field water-holding capacity.
Variety classification of purple sweet potato
1. Jizishu No. 1: Jizishu No. 1 was bred by the Crop Research Institute of the Shandong Academy of Agricultural Sciences and passed Shandong provincial approval in July 2012. Its outstanding feature is the “three highs”. First, high anthocyanin content, with an average content of 76.38 mg/100 g fresh sweet potato. Second, high dry matter and starch content, with dry matter content of 36%-40% and starch content of 25%-27%. Third, high yield potential. Through measures such as plastic film mulching, formula fertilization, whole-growth-period chemical regulation, and effective prevention and control of pests and diseases, standardized and large-scale planting can fully realize the yield potential of this variety.
2. Jishu No. 18: Jishu No. 18 was bred by the Crop Research Institute of the Shandong Academy of Agricultural Sciences, with a yield of more than 3000 kg per mu.
3. Guangshu 135: Guangshu 135 was bred by the Guangdong Academy of Agricultural Sciences, with a yield of 2000-2500 kg per mu.
4. Ningzi No. 4: Ningzi No. 4 was bred by the Grain and Oil Crop Research Institute of the Jiangsu Academy of Agricultural Sciences, with a yield of about 500 kg per mu.
5. Jingshu No. 6: Jingshu No. 6 is produced by crossing Brazilian sweet potato with Chinese sweet potato. It has long stems and vines, purple skin and flesh, high sweetness, and good quality. Its yield is 1500-2000 kg per mu, and its dry matter rate is high. It is mainly used for deep processing and pigment extraction.
6. Zishu Wang: Zishu Wang has high yield and outstanding quality, purple-black skin, purple flesh, is rich in selenium, has a sweet, fragrant and glutinous taste, and delicate flesh. It is an excellent sweet potato variety for fresh eating and health care, especially suitable for making sweet potato paste, sweet potato puree, fried sweet potato chips, etc., and is the preferred variety for making a series of purple sweet potato leisure health foods.
7. Japanese Lingzi: Japanese Lingzi is a new black sweet potato variety introduced from Japan in recent years. The leaves are purple-green, the top three leaves are purple-red, the veins and petioles are all green, the leaves are heart-shaped with shallow single lobes, the vines are about 1.5 m long, and there are few branches at the base. The tuber is long spindle-shaped, with bright purple-red skin and purple-black flesh that turns nearly black after cooking. It is sweet, fragrant, mealy and sandy, rich in anti-cancer substances such as selenium and iodine, and its nutritional components are several times higher than other sweet potatoes. It is currently the darkest variety in the black sweet potato series. It is a good variety for fresh eating, health care, and deep processing such as pigment extraction. It has strong disease resistance and storage tolerance, drought and barren tolerance, and strong adaptability. General yield per mu: spring sweet potato 3000 kg, summer sweet potato 2000 kg.
8. Qunzi No. 1: Developed by the Henan Academy of Agricultural Sciences. Short vines, many branches, high vegetable yield. High yield. Spring sweet potato yields more than 3000 kg per mu, and summer sweet potato about 2000 kg.
9. Yuzi 263: Bred by the Zhejiang Academy of Agricultural Sciences, with a yield of about 2000 kg, delicate flesh, few fibers, high sugar content, and good taste. It is a good variety for eating.
10. Xuzishu No. 1: Entered the Jiangsu provincial sweet potato variety production test in 2003. After five years of trial planting and identification at more than 20 sites, “Xuzishu No. 1” is a new high-yield, purple-fleshed variety. Fresh sweet potato yield is stable at more than 2000 kg per mu, 3-5 times higher than Japanese purple-fleshed varieties “Shanchuanzi” and Ayamurasiky, etc. This variety has red skin and purple flesh; the cooked flesh is bright purple and tastes good. The suitable density is about 3300 plants per mu. It is relatively tolerant of late planting, and waterlogging has a relatively large impact on yield. It is suitable for planting in most areas of northern China and the middle and lower reaches of the Yangtze River.
11. Nanzishu 008: Nanzishu 008 is a new variety bred by the Nanchong Academy of Agricultural Sciences in Sichuan Province. The top leaves are purple-red, mature leaves are green and medium-sized, the tuber is long spindle-shaped, the skin is purple, the flesh is purple, the skin is smooth, the tuber shape is attractive, and the cooked food quality is excellent. Spring cultivation generally yields about 19500 kg/ha of fresh sweet potatoes and about 31500 kg/ha of vine leaves. Autumn cultivation yields 9750 kg/ha of fresh sweet potatoes and 12750 kg/ha of vine leaves. Cultivating this variety as an autumn sweet potato can not only increase fresh sweet potato yield, but also provide fresh green feed for the breeding industry in autumn and winter.
12. Zhezishu No. 1: From the Institute of Crops and Nuclear Technology Utilization, Zhejiang Academy of Agricultural Sciences. In the 2007 provincial sweet potato variety comparison test, the average fresh sweet potato yield per mu was 2148.7 kg, an increase of 49.7% over the control 1 Yuzi 263, reaching an extremely significant level. This variety has good sprouting ability, vigorous seedling growth, long stems and vines, heart-shaped serrated leaves, and green leaf color. Tuber formation is concentrated, with a relatively large number. The average number of tubers per plant is 5.1, the average single tuber weight is 106.1 g, and the proportion of medium tubers of 50-250 g is 58.7%. The tubers are spindle-shaped or long spindle-shaped, with purple skin, purple flesh, and smooth surface. The dry matter rate of tubers is 35.3%, and the steamed fresh sweet potato tastes relatively sweet and mealy. According to identification by the Xuzhou National Sweet Potato Research Center, it is highly resistant to stem nematode disease, resistant to root rot and vine cutting disease, moderately resistant to black spot disease, and has good storage tolerance.
13. Guangzishu No. 1: The top leaves are purple at the edges, the leaf shape is shallow compound, the veins are purple, the stems are green with purple, and the plant shape is semi-erect. The tuber has purple-red skin and purple flower-like flesh, the tuber shape is spindle-shaped and relatively attractive, storage tolerance is good, and sprouting ability is good. The dry matter rate is 30.62%, the eating quality score is 81.3 points, the starch rate is 19.51%, and the vitamin C content is 23.54 mg per 100 g. It is moderately resistant to sweet potato blast disease. It participated in the provincial high-quality group regional test from 2002 to 2003. Based on the comprehensive results of the two-year regional test, the average fresh sweet potato yield per mu was 2375.0 kg.