The use of Nashi pear, Pyrus pyrifolia var. culta,sawdust as a substrate for "Hiratake," Pleurotus ostreatus cultivation, was investigated. Fruit body yield on the pear sawdust substrate was as high as that on "Sugi," Cryptomeria japonica, sawdust substrate, which is regularly used in Pleurotus cultivation. Chemical analysis showed that the pear sawdust contained more replete free sugars needed for mycelial growth than Sugi sawdust. The pear sawdust for Pleurotus cultivation should be made up of coarse particles originally processed from a wood-mill machine. The substrate should be prepared with 65% (wet wt/wet wt) moisture content and 40% (oven dry wt/oven dry wt) wheat bran, and applying "Kinkaki," scratching and flooding, treatment on five days after the complete spawn run. The results could help to address some of the world's current environmental problems by conserving resources and bioconverting ligno-cellulose materials.

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The genetic constitution of B incompatibility factors in Lentinula edodes was estimated by a recombination test. We isolated B factor recombinants in monosporous isolates from a cultivated strain from Japan and a wild strain from Papua New Guinea. By an intrastrain mating test between B factor recombinants, these recombinants were classified into two groups in a cultivated strain from Japan and at least four groups in a wild strain from Papua New Guinea. These results suggest that the third mating type locus, Bγ, is linked to Bα or Bβ in a wild strain from Papua New Guinea and imply that a putative Bγ locus is the same in allelic specificity or absent in the two component homokaryons in a cultivated strain from Japan.

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Analysis of DNA from cultivated mushrooms is difficult for growers who are not familiar with molecular biology techniques. We developed a simple method for distinguishing commercial strains of shiitake mushrooms (Lentinula edodes) using the FTA filter card. Three kinds of shiitake samples were examined: colony grown on an agar plate, mycelium grown on an agar slant, and a fruiting body. Each sample was pressed directly on an FTA card. A portion of the xylanase (xyl) and glucoamylase (gla1) genes was amplified by PCR from 1.2-mm discs cut from the FTA card. After digesting the PCR products with restriction enzymes MspI and HaeIII, the restriction fragment length polymorphism (RFLP) results of two commercial strains were compared. FTA discs originating from three samples of shiitake were successfully amplified by PCR. Two commercial strains were easily distinguished by RFLP of xly and gla1 on an agarose gel. The described method does not require purifying DNA from samples, and no equipment other than the apparatus for PCR and agarose gel electrophoresis is necessary. The method would be widely applicable for mushroom growers as a simple method for typing strains.

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