Interactive effects of heat shock and culture density on embryo induction in isolated microspores culture of Brassica napus L. cv. Global

High yield and good quality embryos were obtained from cultures of isolated microspores of Brassica napus L. cv. Global. The donor plants were grown in a growth chamber at 15/10°C (day/night) with a 16/8h photoperiod. Microspores were isolated from whole buds of 2.5-3.5 mm in length containing late-uninucleate and early-binucleate microspores. Different heat shock treatments including, 30°C for 10, 14 and 18 days, 32°C for 2 and 3 days and 35°C for 18h followed by 30°C for 10 days and various culture densities including 60,000, 40,000 and 20,000 microspores per ml were used. Results showed significant differences among the heat shock treatments, the culture densities and their interaction for embryo induction. A large number of embryos were obtained from the microspores treated at 30°C for 18 days, 35°C for 18h followed by 30°C for 10 days and 30°C for 14 days with a density of 60,000 microspores per ml.