Abstract: Culture conditions for embryogenic callus induction from immature zygotic embryos of Picea koraiensis were studied. The effect of basal medium, light conditions, collection period of immature seeds on induction rate of embryogenic callus were compared through L₁₆(4²×2) mixed level orthogonal experiment, subsequently culture temperature optimization experiment were also performed. The results were as follows: the optimal basal medium and culture conditions were improved RJW medium, dark culture, zygotic embryo collection date of July 20, culture temperature of 22 ℃。The highest embryogenic callus induction rate(81.3%) was achieved on the improved RJW medium supplemented with 1.0 mg·L^-1 BA, 5.0 mg·L^-1 NAA, 20 g·L^-1 sucrose, 450 mg·L^-1 L-glutamine, 750 mg·L^-1 casein hydrolysate, 2.0 g·L^-1 gelrite, dark culture under 22℃, the average induction frequency was 81.3%.

Key words: Koyama spruce, somatic embryogenesis, induction rate