Efficient Production of Doubled Haploids as Isogenic Line Founders via Double Heat Shock Treatment in Willow Gudgeon (Gnathopogon caerulescens)

Doubled haploids (DHs) are essential founders for breeding via isogenic line production. We determined the optimal timing of first and second (HST1 HST2) double heat shock treatment DH production in willow gudgeon (Gnathopogon caerulescens). Gynogenesis was induced by fertilisation with UV-irradiated sperm (20 mJ/cm2). Each HST performed at 40.5°C 1 min. In experiment I, HST1 applied 23–31 min after induction gynogenetic development (incubated 20°C). HST2 15 treatment. When started 25–26 activation, normally hatched larvae appeared relatively frequently (35.6–100%), most were DHs. II, 26 10–25 HST1. Starting 10 resulted 33% more than starting 22.5–25 after. DHs prevalent among (45.1% 20.8%, respectively) when performing 10–12.5 Under appropriate timing, gynogens zygote stage, early prophase, prophase or prometaphase cell cycle. These results establish