Bashan Walnuts

Bashan Walnuts

　　Bashan walnuts refer to walnuts produced in the Bashan area of Chongqing. The walnut kernels have a delicious taste, are highly nutritious, rich in oil content, and high in protein. In addition, they contain calcium, phosphorus, iron, potassium, and various vitamins, making them a highly nutritious dried fruit and an important traditional Chinese medicinal material. -

　　　Walnuts are a highly valuable economic woody species suitable for both fruit and timber production, widely distributed with abundant resources. Their nuts and timber hold significant value. Internationally, walnuts share a similar economic status with almonds, cashews, and pistachios, while domestically they are grouped with chestnuts, persimmons, and jujubes as the “Four Major Dried Fruits.” Walnut kernels contain 60–75% fat, 14.5–24% protein, 8.41–11.04% sugar, and up to 19 types of amino acids, along with rich vitamin content. As such, they have long been a beloved fruit in China, used both for consumption and in medical and health applications. Abroad, they are an essential treat during “St. Nicholas Day” and “Christmas,” earning them the title of “precious fruit.” Every 100 kilograms of walnut kernels can yield 50–60 kilograms of oil. The oil has a fragrant flavor, is pleasant to eat, and also serves as excellent industrial oil. The wood of the walnut tree is tough, with a beautiful grain, resistant to warping and cracking, and capable of withstanding impact, making it ideal for manufacturing airplanes, military equipment, and high-end furniture. As a result, dozens of countries around the world actively promote walnut production. In China, walnuts are also a traditional export commodity, occupying an important position in international trade markets. -

　　Morphological Characteristics

　　 Walnut Catkins

　　　　The walnut is a deciduous tree that can grow up to 35 meters tall. Its bark is grayish-white with shallow vertical fissures. The branches have flaky pith, and the young twigs are covered with fine soft hairs at the tips; older branches are usually hairless. The pinnate compound leaves are 25–

　　50 cm long, with 5–9 (rarely 13) leaflets. The leaflets are elliptic-ovate to oval in shape, with the terminal leaflet usually larger, measuring 5–15 cm in length and 3–6 cm in width. The leaf apex is acute or acuminate, and the base is rounded or cuneate, sometimes cordate. The margins are entire or have indistinct blunt teeth. The upper surface is dark green and hairless, while the lower surface has only fine hairs in the vein axils. The petiolules are extremely short or absent. The male catkins are 5–10 cm long, with male flowers having 6–30 stamens and 3-lobed calyces. Female flowers are borne 1–3 together, with 2-lobed red styles. The fruit is spherical, about 5 cm in diameter, and grayish-green. When young, it is covered with glandular hairs, but becomes hairless when mature. The inner nut is spherical, brownish-yellow, with an irregularly grooved surface. The flowering period is from March to April, and the fruiting period is from August to September. -

　　Post-Harvest Green Husk Treatment of Walnuts

　　　　After harvesting, the fruits are dipped in a 0.3%–0.5% ethephon solution for about 30 seconds, then stacked in a cool place or indoors to a thickness of 50 cm. Under conditions of 30°C temperature and 80%–95% relative humidity, the hulls will separate from the shells in about 5 days, with a dehulling rate of up to 95%. The duration of ethylene ripening and the concentration of the chemical depend on the maturity of the fruit. Higher maturity levels require lower concentrations and shorter ripening times. After ripening, the green husks can be removed manually or by using a dehulling machine.

　　Functional Uses

　　　　Walnut kernels have a delicious taste, are highly nutritious, rich in oil content, and high in protein. In addition, they contain calcium, phosphorus, iron, potassium, and various vitamins, making them a highly nutritious dried fruit and an important traditional Chinese medicinal material. Walnut oil is flavorful and aromatic, serving as a premium edible oil and high-quality industrial oil. The wood is hard and used in military equipment and high-end furniture. The bark, leaves, and fruit husks are rich in tannins, making them useful for dyes and leather tanning. The shells can be processed into activated carbon. Especially when walnut kernels are processed into products such as pastries, peach slices, cakes, and sweet dumpling fillings, their economic value increases significantly.

　　Origin Introduction

　　　　Chengkou is located deep within the Bashan Mountains. Chengkou walnuts are known for their delicious taste, thin shells, and crispy texture, making them a gourmet delicacy. Since 1990, Chengkou County has implemented the “2515” walnut project, which includes measures such as variety improvement, enhanced cultivation management, improved pruning techniques, timely harvesting, and processing. These efforts have led to expanded planting areas and increasing annual yields. The county now has 180,000 mu (approximately 12,000 hectares) of walnut trees, totaling 8 million trees, with an annual output of around 5 million kilograms. Gaoguan Town is particularly famous for its “Wumi Zi” walnuts, which have plump kernels and a unique flavor, and are eagerly purchased by merchants from all over the country every year. Thanks to this, Chengkou has gained widespread fame and was named the “Hometown of Chinese Walnuts” by the National Forestry Department in 2001.