The seedless lime (Citrus latifolia Tanaka) was introduced to Viet Nam in 1994 and later cultivated in Ben Luc, Long An. The tree has broad adaptability, capable of growing in various ecological regions from hilly areas to alluvial-rich lands. The seedless lime cultivation area in Long An is considered the largest in the country, with a concentrated area of over 10,000 hectares, of which Ben Luc accounts for more than 60%. 

The reputation of Ben Luc Long An seedless limes is not only reflected in their scale and export value but also through prestigious awards such as "Typical national agricultural products" by the Central Committee of the Viet Nam Farmers from 2014 to 2017. 

 

Photo: Seedless lime from Ben Luc, Long An 

Seedless lime from Ben Luc, Long An has distinctive sensory properties such as: Firm fruit with thick segments; dark green, bright, uniformly colored peel with numerous essential oil glands on the surface. Fruit weight: 55–77 grams; Fruit length: 5–7.5 cm; Fruit diameter: 4–6.3 cm. Juice yield: 42.6–49.9%; Vitamin C content: 37.3–40.5 mg/100g; Organic acid content: 6.6–7.8%; Lime essential oil content: 0.21–0.24%. 

The distinctive properties of the seedless lime from Ben Luc, Long An are attributed to the unique natural conditions and cultivation techniques of the geographic region. The designated geographic area has an average monthly temperature ranging from 26.3 to 29.7°C, remaining relatively stable throughout the year. The daily sunlight duration in the region fluctuates between 7 and 9.5 hours, with the dry season months reaching higher values: 222–295 hours/month. The geographic area experiences 10 to 11 months with sunshine hours exceeding 200 hours/month. The consistent light exposure throughout the harvest cycle stimulates chlorophyll synthesis and inhibits phytochrome activity, deepening the fruit's color and slowing the peel's color transformation process. The high vitamin C and organic acid content of the Ben Luc, Long An seedless lime are linked to the enhanced biosynthesis mechanism that regulates the fruit's physiological activity under prolonged heat exposure. The region's high temperatures, abundant sunshine hours, and extended daylight duration encourage the lime trees to produce more vitamins and secondary compounds, protecting the plant from adverse effects, enhancing antioxidant capacity, and regulating its physiological functions. 

The soil conditions of the geographical area consist of a light loam structure, a mixture of three soil types: sandy, alluvial, and clay; it has good water retention, adequate aeration, and is rich in nutrients (average NH4+ content reaches 5.12 mg/100g), with high organic matter content and mild acidity (ranging from 5.5 to 6.5). These soil properties in the geographical area help inhibit the conversion of chloroplasts to chromoplasts in the lime peel, slowing down the color change process in the peel. As a result, the seedless lime from Ben Luc, Long An has a darker green color compared to seedless limes grown in Binh Duong and Hau Giang. 

The unique cultivation techniques of the local people in the geographical area are factors contributing to the distinctive characteristics and quality of the product. Propagation is done through grafting. The scions used are from trees that have been controlled through variety pedigree records and sampled for quality assessment before grafting. 

In addition to standard technical procedures, residents in the geographical area apply additional pruning techniques. At the beginning of the rainy season (March to April in the lunar calendar), they prune the trees, focusing on removing crossed branches, overlapping canopies, and overgrown branches at the top two-thirds of the tree's height on the western side. This technique ensures the ventilation of branches and leaves, enhancing the ability of seedless limes to receive sunlight at most fruit-bearing positions. It is a key factor influencing the fruit's peel color (dark green) and the higher accumulation of vitamin C and organic acids compared to seedless limes grown in Binh Duong and Hau Giang. 

Residents in the geographical area apply organic fertilizer twice a year, at the beginning and end of the rainy season, using 5–10 kg per tree annually (2–5 kg per tree per application). The types of organic fertilizers used include composted manure (cow dung, chicken manure, etc.). The secret to organic fertilization lies in enhancing the soil's content of readily available organic matter (directly usable by plants), such as nitrogen, phosphorus, potassium, and especially NH4+ levels, which contribute to the deep green color of the rind of Ben Luc Long An seedless limes. Additionally, organic fertilizer improves the physical properties of the soil, increasing its porosity and microbial activity, particularly the presence of Micorhiza fungi that parasitize the root epidermis, thereby enhancing the plant's ability to absorb water, mineral salts, and organic compounds. 

The seedless lime in the geographic region is harvested from the 120^th to the 130^th day after flowering. Early harvesting techniques affect the firmness of the fruit and the thickness of the juice sacs. The seedless lime from Ben Luc, Long An has an earlier harvest time compared to the control region, resulting in smaller fruit weight (only 55–77 grams/fruit) and smaller, thicker, less plump juice sacs. When harvested while still green, pectin exists as insoluble protopectin in water, playing a role in stabilizing the shape and enhancing firmness, thereby increasing the fruit's firmness. The juice yield is directly influenced by the fruit's juice sacs. The seedless lime from Ben Luc, Long An has thick juice sacs and low juice sac plumpness, so the juice yield contained in the sacs is lower compared to the seedless lime from the control region. The essential oil content in the peel of the seedless lime from Ben Luc, Long An is closely related to the peel surface structure and juice yield. The peel surface of this lime has numerous oil glands (the rough peel surface due to light exposure facilitates the formation of oil glands). Additionally, the juice sac plumpness is not yet high, so there is insufficient force exerted on the fruit surface, allowing most of the essential oil to remain trapped in the oil glands on the fruit surface. 

The geographical area includes: Ben Luc town and the communes of An Thanh, Binh Duc, Long Hiep, Luong Binh, Luong Hoa, My Yen, Nhut Chanh, Phuoc Loi, Tan Buu, Tan Hoa, Thanh Duc, Thanh Hoa, Thanh Loi, and Thanh Phu in Ben Luc district; the towns of Duc Hoa, Hiep Hoa, Hau Nghia and the communes of An Ninh Dong, An Ninh Tay, Duc Hoa Dong, Duc Hoa Ha, Duc Hoa Thuong, Duc Lap Ha, Duc Lap Thuong, Hoa Khanh Dong, Hoa Khanh Nam, Hoa Khanh Tay, Huu Thanh, Loc Giang, My Hanh Bac, My Hanh Nam, Tan My, Tan Phu, and Hiep Hoa in Duc Hoa district; Dong Thanh town and the communes of Binh Hoa Bac, Binh Hoa Hung, Binh Hoa Nam, Binh Thanh, My Binh, My Quy Dong, My Quy Tay, My Thanh Bac, My Thanh Dong, My Thanh Tay in Duc Hue district; Thanh Hoa town and the communes of Thuy Tay, Thuy Dong, Thanh An, Thuan Binh, Tan Hiep, Tan Tay, Tan Dong, Thuan Nghia Hoa, Thanh Phu, Thanh Phuoc in Thanh Hoa district; Thua Thua town and the communes of Long Thanh, Tan Thanh, Long Thuan, My Lac, My Thanh, Binh An, Nhi Thanh, My An, Binh Thanh, My Phu, and Tan Long in Thua Thua district, Long An province. 

Source: Bảo hộ chỉ dẫn địa lý "Bến Lức Long An"   

cho sản phẩm Chanh không hạt   

Translator: Nguyễn Hải Phong