Seedless king orange: Expectations for an export breakthrough

Breeding superior orange varieties

As mentioned by the Southern Horticultural Research Institute (SOFRI), over the past time, king orange has been cultivated widely by farmers in some Mekong Delta provinces namely Tien Giang, Hau Giang, Ben Tre, Soc Trang, Vinh Long, and Tra Vinh among others. However, seedy and thick skin are the weak points of this orange variety that make it hard to meet the increasingly high demand of consumers for fresh fruits and juices.

Besides, the plant variety frequently suffers from three diseases: greening, root rot, green veining, and triteda, which are difficult to treat. 

Dr. Tran Thi Oanh Yen and scientists from SOFRI have researched the king orange variety, creating new varieties/lines with high disease resistance, seedless or a few seeds, beautiful fruit shape, and delicious quality from commercial orange trees are popular in production. “The number of seeds in orange is one of the factors limiting fresh oranges and tangerine consumption in both domestic and foreign markets. Therefore, in the selection and breeding of citrus trees in Vietnam as well as in the world, the main goal is to categorize seedless, beautiful, delicious varieties, resistant to pests and dangerous diseases, "said Yen.

According to Dr. Yen, with the method of selection and mutation by gamma rays, a seedless orange line named LD6 was created with many outstanding characteristics such as a high percentage of sterile pollen grains (70%), a low number of seeds/fruit (less than 2 seeds/fruit) and stable in all fruits in all trees. This new strain of oranges has a beautiful bright orange-yellow flesh, less lumpy and glossy skin compared to the current oranges. The average fruit weight of LD6 is 237 grams, with a lot of juice (over 40%), sweet and sour taste, characteristic aroma. The yield of LD6 is quite high (20-25kg/plant/year for 3-year-old trees).

To maximize the effectiveness of the variety, SOFRI spends a lot of time researching the process of planting and caring for LD6 seedless orange trees according to VietGAP standards. Accordingly, besides the measures of pruning to create a canopy, applying organic fertilizers among others, the process also clearly identifies the composition of pests and diseases and the composition of beneficial microorganisms on the orchard for farmers to apply more effective prevention measures. Ensuring food hygiene and safety, without residues of pesticides, meeting the increasing requirements of consumers.

While cultivating follows VietGap standard, the LD6 seedless king orange is not only limiting the dangerous diseases, but this variety may produce a yield of over 10-15 tons per crop per hectare and an average of 35 tons per hectare for mature oranges after three years of cultivation, with prices ranging from VND 15,000-25,000 per kilogram, bringing high and stable income to farmers.

With these aforementioned outstanding strong points, SOFRI’s seedless king orange has been granted Certification of Plant Variety Protection by the Department of Crop Production (MARD) in 2019.

Seedlings have a 99% survival rate

SOFRI cooperated with the Department of Agriculture and Rural Development in Tra Vinh to implement the project of transferring technical advances and build a model of breeding and planting high-quality seedless king oranges for farmers to apply in production. Initially, it achieved many positive results.

According to the Agricultural Extension Center of Tra Vinh province, in 2019, the center cooperates with the Tra Vinh Seed Center to produce 100,000 disease-free LD6 seedless king orange seedlings in a net house with an area of 900 m2 in Chau Thanh district. 

Thanks to good seedlings and adaption to the land condition in the local in addition to the advanced cultivation, all plants are healthy, free from pests and diseases, with good yield and quality. In fact, seedless king oranges have a higher value of 30 to 50% than normal oranges due to the reduction in investment costs of fertilizers and pesticides, so they are strongly supported by local authorities and people.

Talking to Vietnam Agriculture Newspaper, Le Van Lam, Director of the Agricultural Extension Center of Tra Vinh province, said that Tra Vinh province has over 3,200 hectares of oranges, mainly concentrated in Cau Ke district, cultivated in the area of over 2,000 hectares. Up to now, the local orange varieties are in a state of degradation, so their ability to withstand the harshness of the environment and pests is decreasing, the yield and quality of the fruit are also gradually decreasing. Meanwhile, LD6 seedless king orange has many good traits such as beautiful, succulent, and sweet fruit, so it is highly competitive in the market.

“This is the first safe seedless king orange production model in Tra Vinh province, helping people earn much money. In the coming time, the locality will re-evaluate its productivity and efficiency, and on that basis will conduct the duplication. At the same time, strengthen trade promotion to introduce products, contributing to improving the value of diversifying local crop products," emphasized  Le Van Lam.