Pineapple (Ananas comosus L.) is an important tropical fruit of Vietnam as it has a high demand for local and export markets. In Vietnam, the Queen pineapples have been cultivated for a long time in the alum soil of Mekong delta. Total area under Queen pineapple cultivation was approximately calculated of 34,857 hectares that produced 585,120 tons of fruit (FAO, 2014). Flowering process of pineapple is related to chemical substances used, concentration, the situation of plant vegetative growth that affect to flowering time, flowering rate and yield of fruit. 

The team screened the proper chemical and concentration, some field trials with different doses of calcium carbide (5, 10, 15 g/L) and ethephon (30 & 60 ml/L) were carried out in Tan Phuoc district, Tien Giang province during 2013-2014 period.

Results conducted from the study showed that application of ethephon 30 ml/L reduced weight of fruit, increased flowering rate, yield compared to control experiments implemented by local growers. The flowering rate of 96.1% in the first harvest season and 92.1% in the second were recorded at ethephon 30 ml/L treatment whereas the yields of 61.5 and 45.2 tons per ha in the above mentioned treatment. The yield of 48.9 and 39.5 tons per ha at control treatment was observed in harvest seasons respectively.