Ha Thi Thuy, who successfully developed 52 varieties of plants

In 1990s, Vietnam had many precious orange varieties grown in many localities. However, the oranges had many seeds. Thuy was then assigned by her teacher – Prof Do Nang Vinh – to seek good genetic sources to create a seedless variety.

In order to obtain seedless orange variety, it was necessary to produce triploid varieties by crossing tetraploid and diploid varieties. However, Thuy met with difficulties because of the lack of suitable tetraploid genetic sources.

She decided to work on good native varieties such as Van Du orange, Song Con, thick-skin orange, Chum mandarin and Phuc Trach pomelo. She selected branches, removed leaves and top shoots, cleaned them and treated with colchicine. After several selections, she got trees which had thick and large leaves, of the tetraploid genre.

However, the cultivation was heavily influenced by weather conditions. Orange and pomelo trees only bloom once a year, and if weather conditions are unfavorable, it will be impossible to create the desired varieties. She experienced some failures because of the weather.

Reaping fruit

Thuy finally created V2, a seedless orange variety, from Valencia Olinda with strong plants and higher yield than the original variety, which was recognized by MARD as the official variety in Vietnam.

The orange contains 0-6 seeds, or 4.5 seeds on average in the intercropping conditions (Xa Doai orange has 19.5 seeds on average). V2 is a late ripening variety with broader adaptability and disease resistance than other varieties.

The method applied by Thuy was highly appreciated by Prof Do Nang Vinh, who said it opened a new way of creating fruit tree varieties with no seeds, fewer seeds or smaller seeds.

Thuy believes that developing new citrus varieties can become the strength of Vietnam's agricultural science because Vietnam has advantages in orange genetic sources. 

Xa Doai orange, Chum mandarin, Phuc Trach and Red pomelo are rare and precious gene sources essential for the development of seedless citrus in the time to come.

Thuy and her co-workers have created 52 plant varieties, of which 20 have been recognized as national varieties.

The scientist said she was happy that she could help farmers get a higher income and better living standards. 

Dinh Van Oanh, who is called ‘Orange King’ in Ha Tinh province, is one of the farmers. He bought 500 seedlings to grow V2 orange. The satisfactory farming results allowed him to pay debts and make a profit.

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