EFFECTS OF PRIMORDIUM FORMATION METHOD AN D MOISTURE-CONTENT OF MEDIUM ON FRUITING BODY PRODUCTION OF ARMILLARIA SPECIES

We investigated the fruiting body production of a Armillaria mellea (V ahl : Fr.) Kummer complex in bottle cultivation. Two strains of the A. mellea complex (HFP-Am 82-10 and HFP-Am 82-14) were incubated in cult ivation bottles of 800 ml containing medium (birch (Betula ermani Cham .) and rice bran) at 22 degrees C and 70% humidity in the dark for 35 or 63 days. After incubation, the bottles were put into 16 degrees C a nd 85% humidity conditions under intermittent illumination with 350 lx alternates with the dark every 12 hours for fruiting. The bottles inc ubated were covered with ST-caps which were made of polypropylene and were not equipped with filters, to avoid drying of the culture sufaces during primordium formation. For HFP-Am 82-14, primordia were formed synchronously, and all cultures produced fruiting bodies whithout fung i contamination at 66-75% moisture content of the medium. On the other hand, when the bottles were covered with moist uretane sheet instead of the caps, periods to primordium formation and to cropping after the treatments for fruiting, varied widely from bottle to bottle at 72% m oisture content of the medium. In addition, some cultures produced no primordium mainly because of fungal contamination. Furthermore, the ve ntilation capacities of the caps used for the fruiting, affected primo rdium formation and yield of the fruiting bodies. For HFP-Am 82-14, th e period to primordium formation was shortend 14-18%, and the yield in creased to 64-69% at 66% moisture content of the medium by the use of two kinds of ST-caps of different light transmittances, compared with paper-caps. The ST-caps surpassed the paper-caps with regard to ventil ation. The yields of fruiting bodies showed maxima for the two strains when cultivated with about 71% moisture contents media. The maximum v alues for average fresh weights per bottle were 105 g for HFP-Am 82-10 and 101 g for HFP-Am 82-14. Their periods to primordium formation and to cropping after the treatments for fruiting were about 10 and 25 da ys, respectively.