Received: 11-02-2020 / Accepted: 12-08-2020
The experiments were to determine optimal technical practice for F1seed production of hybrid rice cultivars HQ21 for highest yield. They were carried out in 2018 summer season on the field of Crops Research and Development Institute of VNUA, Gialam district, Hanoi.The technical practices are sowing season, row ratio of male: female lines, transplanting density of female line, fertilizer dose and GA3spraying dose. The parental lines were sown into 8 seasons, each day separated by 07 days. Percentage of parents is arranged with 04 different formulas in the form of RCB design. Four transplanting density and 4 different fertilizer doses arranged in Split-plot design. Experiment to determine the appropriate GA3spraying dose for F1hybrid seed production field is arranged in a RCB design.The results show that, the sowing date of parental lines was recommended such that heading date of parental lines set in from 25thAugust to 10th September, female line was sown 5 days before male line, row ratio of male:female was 2:14, transplanting density of female line was 50 hills/m2, fertilizer dose was 120kg N + 60kg P2O5+ 60kg K2O/haand the amount of GA3sprayed per hectare was 160 grams of pure.