【Objective】The relativity between asymmetric nuclear division and strain degeneration was discussed to elucidate mechanism of strain degeneration in Volvariella volvacea. 【 Method 】 Three degenerated Volvariella volvacea strains were selected according to RAPD markers and colony morphology. The number and size of nucleus of a normal strain and three degenerated strains of Volvariella volvacea, PYb5, PYb6, PYb7, were observed and compared by nucleus staining. 【Result 】The results showed that many nucleuses e...