• Journal of Mushroom
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• v.4 no.2
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• pp.48-52
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• 2006

Oyster mushroom, Pleurotus ostreatus is bifactorial heterothallism. Single basidiospore isolates from fruiting bodies are homokaryotic and self-sterile. However, we found that homokaryons derived from some strains of P. ostreatus could develop fruiting bodies with two different types. One hundred and two isolates out of 155 monospore isolates formed fruiting bodies (65.8%). First group did not have only mature or sporulating fruiting bodies but also clamp connections, which initial isolate also did not present clamp connections (Abortive homokaryotic fruiting, AHF). Second group had developed fruiting bodies with clamp connections even though initial homokaryotic colony did not form clamp connections (Pseudo- homokaryotic fruiting, PHF). The mycelial colonies derived from PHF by tissue culture formed clamp connections, while mycelial colonies of AHF lacked them. We obtained 535 PHF and 79 AHF inter-strain hybrids among 8 strains of P. ostreatus by hyphal anastomosis. The fruiting body yield of PHF group is higher than that of AHF group in bottle cultivation. A preselection of single spore isolates for fertility would save labour in strain improvement of P. ostreatus.