NGHIÊN CỨU TUYỂN CHỌN VÀ KHẢO NGHIỆM GIỐNG NHÃN CHÍN SỚM TẠI TỈNH HƯNG YÊN

Longan is considered one of the main fruit crops of Vietnam. However, currently, structure of late longan varieties is unbalanced including 90% of main longan varieties, 7-8% of late longan varieties and small percentage of early varieties. Therefore, since 1997, the Fruit and Vegetable Research Institute have conducted evaluation and selection of early longan varieties with high yield, good quality and harvested during 15 - 30 July. Up to 2012 the project chose 7 early longan trees in Hung Yen province and coded PHS 1 to 7, in which the two oldest longan tree were 50 years old and the youngest one was 11 years old. Of the 7 selected longan trees, PHS 1 has many superior characteristics such as 3-year average yield of 116 kg of crop, large, round fruit, thin, smooth fruit skin with bright yellow, dry, brittle flesh. Due to the above superior characteristics, the project has selected PHS 1 for evaluation in Khoai Chau and Kim Dong districts, Hung Yen province since 2011. The results showed that flushing times and the size of flushing times of the tested longan vatiety were similar to the control (Huong Chi variety). Its fruit weight, pulp percentage and brix were equivalent to Huong Chi one at 12.4 g, 66.8% and 21.1%, respectively. The average yield of 10 year old trees reached 55-65 kg/plant, harvesting time was 20 - 26 July and 22-24 days earlier than the control. The longan tested orchard was attacked by many pests and diseases at slight/mild level. Due to the early harvesting time, large fruits, good appearance and good quality, it gave quite high net return, averaging from VND 249,700-287,500 dong and 1.5 to 1.9 times higher than the control (Huong Chi variety).