Abstract
The mchanism for re-dikaryotization of the oidium-derived monokaryotic mycelium with the parental dikaryotic mycelium in the cultivation on Pholiota nameko was investigated. The oidium-derived isolate produced dikaryotic mycelium in the dual culture with an other mating type of oidium monokaryon or a parental monokaryon that carried a different incompatibility factor. The rate of redikaryotization in the oidium isolates containing the dominant nucleus that was found to be only 19%. On the other hand, the rate of the dual cultures in the oidium isolates having the recessive nucleus with the parental dikaryons was 89%. These results suggest that the re-dikaryotization of monokaryotic oidium isolates is performed by the Mon-Mon mating in the dual cultures of the oidium isolates having the recessive nucleus with the monokaryotized mycelia from the dikaryotic mycelia. The most of re-dikaryotization products of the oidium-derived isolates with the parental monokaryons and the dikaryon showed the delay of fruiting and the decrease in yields of fruit-bodies as compared with the corresponding results with the parental dikaryotic stocks. These detrimental results might be caused by the variation in phenotypic characteristics produced in the process of monokaryotic oidium formation occurred in the spawn running of this mushroom.
