[Studies on fused recombination of Gibberella fujikuroi--gibberellin-producing strain].

A pair of nutrient complementary auxotrophic mutants were used as fusion parents. Their protoplasts were prepared enzymatically and PEG4000 was used as fusion agent. The prototrophic recombinants were selected directly on the minimal regeneration medium. The recombination frequency was about 10(-7). Some unstable heterocaryons were occurred and the frequency was about 10(-5)-10(-6). Mutation of pigment, hyphae morphology and gibberellin production were induced through the fused recombination. The positive mutation, negative mutation of gibberellin yield among the recombinants were 15.3% and 53.1% respectively. Gibberellin yields of recombinants signed RN2 and RG14 were over 25% than that of the prototrophic parent 207 strain.