HQ19 is the two-line hybrid rice combination developed from a cross between aromatic themosensitive genic male sterile line (E155) and Huong com by Crops Research and Development Institute. HQ19 has short growing duration, high yield, long grain, aroma. HQ19 is suitable for growing in the late spring and early summer crop seasons in the Northern provincies of Vietnam. The process of producing Fl hybrid seed of two-line hybrid combination HQ19 was developed successfully in the Northern in summer season. The R2 line should be sowed 17-18 days before of sowing of E15S line, ratio of the R2: E15S line is 2:14, spraying GA3 with 180 gram soluting in 600 liter H2O/hectare.