Miyi Polygonum multiflorum

Miyi Polygonum multiflorum

Miyi Polygonum multiflorum is a protected geographical indication product.

　　Miyi Polygonum multiflorum is a renowned specialty of Miyi County in Panzhihua City, Sichuan Province. Its lecithin content is higher than that of soybeans and deep-sea fish oil, exceeding three times the lecithin content found in Polygonum multiflorum from other regions. It also contains high levels of selenium and iron.

　　Miyi Polygonum multiflorum gets its name from being produced in Miyi County, Panzhihua City, Sichuan Province. Miyi County is located in the Panxi region, where the geological structure is highly unique, resulting in exceptionally rich mineral resources. The Polygonum multiflorum grown here has a lecithin content higher than that of soybeans and deep-sea fish oil, exceeding three times the lecithin content of Polygonum multiflorum from other areas. It also contains high levels of selenium and iron.

　　As the largest Polygonum multiflorum planting and production base in the Panxi region, Miyi County cultivates Polygonum multiflorum using a “company + base + farmer” business model. Miyi Polygonum multiflorum is typically harvested after two to three years. Planting bases practice rotational cropping, rotational harvesting, and cyclic supply. The largest local bioproducts company, Sichuan Pingda Biotechnology, signs planting and procurement agreements with village cooperatives. Farmers follow the GAP (Good Agricultural Practice) cultivation standards provided by the company for growing Polygonum multiflorum, and the company purchases the harvest at a guaranteed minimum price. During cultivation, Pingda provides farmers with Polygonum multiflorum seedlings or seeds, bio-fertilizers, agricultural films, and other inputs. One technical specialist is assigned per 300 acres to address any technical issues promptly, ensuring a yield of at least 1,500 kg per acre. In the process, the company trains over 5,000 farming households in cultivation techniques and employs around 200 people in the production and processing stages.

　　Pingda Biotechnology has developed Polygonum multiflorum cultivation within the county, reaching a planting area of 3,000 acres by the end of 2010. As a biennial plant, Polygonum multiflorum is cultivated using crop rotation. The company plans to expand the countywide planting area to 20,000 acres within three years, with an average yield of 3,000 jin (approximately 1,500 kg) per acre, aiming for an annual production of approximately 15,000 tons.

　　The production area of Miyi Polygonum multiflorum covers the entire administrative region of Miyi County, Sichuan Province.

　　I. Source Material

　　Polygonum multiflorum (Polygonum multiflorum Thunb).

　　II. Growing Conditions

　　The production area lies at elevations between 1,300 and 2,200 meters. The soil types are mountainous red soil (yellow-red soil) and mountainous yellow soil, predominantly medium to heavy loam, with a pH value of 6.0 to 7.5 and 1.0% organic matter.

　　III. Cultivation Management

　　 1. Seedling Cultivation:

　　(1) Seedling Propagation: From January to September each year, select superior and robust Miyi Polygonum multiflorum plants as mother plants for collection.

　　(2) Cutting Propagation: For outdoor seedling cultivation, use small arched film covers. Maintain humidity and temperature (ideal range: 20°C to 25°C) inside greenhouse seedbeds.

　　(3) Seedling Uprooting: Seedlings for transplanting should be 15 cm to 25 cm tall, with 1–2 main roots at least 1 mm thick and 3 cm long, or 3 or more fibrous roots longer than 3 cm. Leaves should be fresh and green, free of pests or disease.

　　(4) Field Transplanting: Conduct transplanting in spring and autumn. Use 4,200 seedlings per 667 m² (1 acre), with one seedling per planting hole.

　　2. Field Management Practices: Miyi Polygonum multiflorum is cultivated using trellising methods with minimal or short vines. Apply 50–100 kg per 667 m² of organic compound fertilizer twice annually—once before leaf growth from February to March and once before flowering from August to September.

　　3. Harvesting: After two years of field cultivation, harvest from October to November. Harvested Miyi Polygonum multiflorum is sorted by size and placed into baskets.

　　4. Environmental and Safety Requirements: The use of pesticides, fertilizers, and other inputs must comply with national regulations, and environmental pollution must be avoided.

　　IV. Processing Procedure

　　Cleaning → Drying → Slicing → Testing → Packaging.

　　V. Quality Characteristics

　　1. Sensory Features:

　　(1) Visual: Miyi Polygonum multiflorum appears in lump or irregular spindle shapes, 6–15 cm in length and 4–12 cm in diameter. The surface is reddish-brown or dark reddish-brown, wrinkled, uneven, with shallow grooves, transverse elongated lenticel-like protrusions, and fine root scars. It is heavy and firm, not easily broken. The cross-section is light yellow-brown or light reddish-brown, powdery in texture, with 4–11 rounded anomalous vascular bundles arranged in rings in the cortex, forming a cloud-patterned design. There is no central xylem core.

　　(2) Olfactory: Strong ginseng-like fragrance.

　　(3) Taste: Slightly bitter with a sweet and astringent finish.

　　(4) Touch: Slices are neat, firm, and not easily broken.

　　2. Physicochemical indicators: Contains 2,3,5,4′-tetrahydroxy-diphenyl-1-2-Ο-β-D-glucoside ≥2.2%.