Chumen Wendi (Pomelo)

Chumen Wendi

Chumen Wendi is a geographical indication certification trademark.

　　Wendi (pomelo), also known as Yuhuan pomelo, luan, or pao, is primarily grown in Chumen Town, Qinggang Town, and key pomelo breeding bases such as Longyan, Mixi, Fangzhuang, and Tongli on the Chumen Peninsula in Yuhuan County, Zhejiang Province. Introduced by pilgrims from Xiamen during the Qing Dynasty's Tongzhi era, it has over 120 years of cultivation history. The Chumen Wendi geographical indication trademark is registered by the Yuhuan County Wendi Special Products Bureau, covering the flatland areas and low mountainous hills below 150 meters altitude within Yuhuan where Chumen Wendi is cultivated.

　　　Chumen Wendi

　　When ripe, the bottom is flat with a slight depression, while the stem end is slightly protruding. The rind is bright orange-yellow with a fragrant aroma, and the fruit is large and heavy. Typically weighing 1.5–2.5 kg, its flesh is crystal-clear, soft, sticky, and juicy, with a well-balanced sweet and tangy flavor, crisp yet seedless, and rich in aroma. The tree thrives in warm, humid conditions but is not cold-resistant, requiring an annual average temperature above 17°C, minimum temperatures not below -7°C, annual rainfall exceeding 1000 mm, and thrives best in slightly acidic or neutral, fertile sandy loam soil.

　　The Chumen Peninsula features a subtropical maritime monsoon climate—mild and humid, with abundant sunshine and distinct seasons. The average annual temperature is 17°C, with 327 frost-free days, and annual rainfall of 1400–1500 mm, distributed relatively evenly.

　　Historical and Cultural Background

　　　　Chumen Wendi is cultivated through selective breeding and grafting, and is highly nutritious. Besides being eaten fresh, its rind can be used to make candied peel, rind candy, and to extract aromatic oils. In December 1982, Chumen Wendi was awarded first place in the pomelo category at the National Citrus Regional Conference; in 1985, it ranked first again at the National High-Quality Agricultural Products Exhibition. It is sold not only in major cities but also exported to Hong Kong, Macau, and Southeast Asia.

　　Suitable Rootstocks for Seaside Chumen Wendi

　　Experimental Development

　　　　Experiments were conducted in 1988 at the Chubeitang Wendi Orchard in Chumen, Yuhuan County. The orchard was reclaimed in the 1970s. The soil pH ranged from 8.3 to 8.5, and the tested trees were 7-year-old Wendi grafted onto local luan rootstocks. Surveys were also conducted on other seaside pomelo orchards, including the impact of different rootstocks on above-ground growth, fruiting, root distribution, phenology, and flowering/fruiting habits. Results showed that Chumen Wendi has strong graft compatibility with local luan, with the graft union swelling downward. The trees grow quickly, vigorously, and begin fruiting 3–4 years after planting. The canopy is tall and large, adaptable to various soils, especially salt-alkali tolerant, with good yield potential. However, when used as a rootstock for flat-fruited Wendi, severe fruit cracking occurs at maturity.

　　Chumen Wendi shows strong graft compatibility with Yucheng (a citrus species), with a balanced graft union. The canopy is smaller and more compact, the tree is robust, and it yields well. The fruits are smaller, with tender juice vesicles and less cracking. Chumen Wendi also grafts well with trifoliate orange (Poncirus trifoliata), with the graft union being smaller on top and larger at the bottom, featuring spiral patterns. The tree grows vigorously, tall, and dense, making it suitable as a rootstock for mountain-grown Wendi. However, in seaside orchards, excessive flowering often leads to severe flower and fruit drop, even with girdling treatments during flowering, resulting in minimal yield.

　　Chumen Wendi grafted onto local luan rootstocks has an inconspicuous taproot, typically with 3–4 thick roots growing vertically downward, along with many lateral and absorbing roots. The horizontal root system extends 1.5–2 times the canopy width, but the densest root concentration is within 1.2 meters of the trunk. Local luan roots are mainly concentrated in the 10–30 cm soil layer, while trifoliate orange roots penetrate deeper, primarily in the 10–40 cm layer. In seaside Wendi orchards, aside from groundwater levels, the depth of the clay layer is a key factor affecting downward root distribution, which must be considered during orchard establishment.

　　China Geographical Indication Registration List

　　　　No.: 23; Geographical Indication Trademark Name: Chumen Wendi; Registration No.: 1299948; Product Category/Name: Wendi (Pomelo); Registrant: Yuhuan County Wendi Special Products Bureau; Geographic Scope: Flatland areas and low hills below 150 meters altitude within Yuhuan, Zhejiang Province, where Chumen Wendi is cultivated.