Trichoderma causes, green mold, and inhibits the harvest of mushroom crops. We analyzed a total of 24 isolates of Trichoderma, Gliocladium and Hypocrea from mushroom facilities and on wild mushrooms, for molecular characteristics. We found random amplified polymorphic DNA (RAPD) markers to be useful for detecting clonal reproductions. A common fragment (A10-2000) was found in the T. harzianum aggregate isolates by RAPD analysis using primer A10. The single strand conformation polymorphisms (SSCP) analysis patterns of the internal transcribed spacer 1 (ITS1) region on the nuclear genome were characteristic of each species and aggregate.

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The effect of using azuki bean-paste refuse as a substrate on the yield and constitution of fruit-bodies in the sawdust based cultivation of Flammulina velutipes (Curt.: Fr.) Sing, was investigated. By replacing the sawdust of Cryptomeria japonica (Lin. fil.) D. Don. (Sugi) with azuki bean-paste refuse, the fruit-body yield in the medium with a substitution ratio of more than 50% became constant and was 1.1 times the yield of the medium where only C. japonica sawdust was used. In the case where Picea jezoensis (Sieb.et Zucc.) Carr. (Yezo spruce) sawdust was replaced by azuki bean-paste refuse, the fruit-body yield increased as the substitution ratio of azuki bean-paste refuse became higher, up to a substitution ratio of 60%, where the fruit-body yield was 1.2 times greater compared to when only P. jezoensis sawdust was used. Though the fruit-body yield in the P. jezoensis (sawdust)・ricebran medium was less than that in the C. japonica (sawdust)・ricebran medium, the fruit-body yield in the medium where P. jezoensis sawdust was replaced by azuki bean-paste refuse at a ratio of 50〜80% was more than that of C. japonica (sawdust)・ricebran. These results suggest that P. jezoensis sawdust is useful as a substrate when mixed with azuki bean-paste refuse. By cultivating F. velutipes on the medium where P. jezoensis sawdust was replaced by azuki bean-paste refuse, the crude protein and crude fat content of the fruit-bodies decreased and the free sugar and free sugar alcohol, organic acid and free amino acid content increased. Especially, the content of arabinitol, glycerol, alanine and glycine in the fruit-bodies increased. Therefore, it was considered that the sweetness of the F. velutipes fruit-bodies was introduced by the increase in these substances.

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Fistulina hepatica Schaeff. : Fr. has been known as a mushroom having antitumor and anti-bacterial properties. In order to obtain much mycelia, several kinds of the nutritional factors affecting mycelial growth of F. hepatica in a liquid culture were examined. Optimum initial pH of the medium was 5.0 and the mycelia had a remarkable character which is that the mycelia could not grow in neutral range from pH 6.5 to 7.0. Corn starch was most effective for growth in the ten kinds of carbon sources, which yielded over twice as much mycelia as glucose. This result suggests that the mycelia of F. hepatica has a superior capability to efficiently use highmolecular polysaccharides for its growth. The effects of nitrogen sources on growth were examined with ten kinds of organic and inorganic materials. Malt extract was the most effective for the growth, and the optimum concentration was 4.0%. In this study, we obtained the fundamental conditions for mass culture of F. hepatica mycelia.

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To establish a cultivation method of morel, we investigated sclerotium formation of Morchella esculenta collected in Japan. Though many sclerotia were formed on Potato dextrose agar (PDA)/noble agar (NA) media, the quality and quantity of sclerotia were different in each strains. Sclerotia were small and white in early stages, then they pigmented as they grew. To investigate sclerotium formation in practical media for fruit-body production, M. esculenta was incubated in grain media and bark-sawdust media, which are commonly used for cultivation of saprophytic mushrooms. The quantity of sclerotia in grain media was higher than in barksawdust media. After sclerotia formed in grain media were transferred onto soil media, sclerotia grew further and rolled up soil or grain residue. This observation supports an opinion that model sclerotia are not true sclerotia but pseudosclerotia. Sclerotia on soil media grew up to 3-4cm in diameter, which is expected that this is enough to form the fruit-body.

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Double-stranded RNA (dsRNA) was detected in discolored strain of cultivated Flammulina velutipes, Shinano No. 6. First, mycelium was ground in phosphate buffer and virus particles were precipitated by PEG 8000 and NaCl added to the mycelial extract. After virus particles were phenol extracted, dsRNA became apparent in the agarose gel electrophoresis. A total of 3 dsRNA; S1 (size 1.4kb); S2 (size 1.6kb); and L1 (size 9.5kb) were present. This was the second example of dsRNA detected in the brown discolored fruit body of Junpakukei Enokitake. Thus, dsRNA could be causal agent for spontaneous brown discoloring of the cultivated F. velutipes.

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