This study was conducted to develop superior hybrids of Pleurotus ostreatus with di-mono and mono-monoka-ryon crosses. Random Amplified Polymorphic DNA-PCR (RAPD-PCR) was used to compare its mitochondrial DNA profiles of hybrids using specific primers designed from microsatellite markers of Pleurotus salmoneo-stramineus. A total of fifty-six dikaryon-monokaryon hybrids were sampled for RAPD-PCR experiments and the results show that twenty-four hybrids were dikaryon and thirty-one hybrids were monokaryon. Interestingly, one hybrid was an intermediate form with the DNA profiles that are different from those of its parents. The DNA profiles from eighty-eight monokaryon-monokaryon hybrids were also analyzed by RAPD-PCR. The results of mitochondria DNA profiles show that seventy-one hybrids are the same to one of their parents, but seventeen hybrids show DNA profiles of both parents.

• Eun Jung Kim(Mushroom Research Division, National Institute of Horticultural & Herbal Science, RDA, 1Suwon 441-707, Korea. Department of food and nutrition, Sungshin women’s university)
• Won Sik Kong( Mushroom Research Division, National Institute of Horticultural & Herbal Science, RDA, 1Suwon 441-707, Korea. Department of food and nutrition, Sungshin women’s university) | Won Sik Kong
• Kab Yeul Jang( Mushroom Research Division, National Institute of Horticultural & Herbal Science, RDA, 1Suwon 441-707, Korea. Department of food and nutrition, Sungshin women’s university) | Kab Yeul Jang
• Pyung Gyun Sin( Mushroom Research Division, National Institute of Horticultural & Herbal Science, RDA, 1Suwon 441-707, Korea. Department of food and nutrition, Sungshin women’s university) | Pyung Gyun Sin
• Yunjung Park( Mushroom Research Division, National Institute of Horticultural & Herbal Science, RDA, 1Suwon 441-707, Korea. Department of food and nutrition, Sungshin women’s university) | Yunjung Park
• Young sook Hahn( Suwon 441-707, Korea. Department of food and nutrition, Sungshin women’s university) | Young sook Hahn
• Young Bok Yoo( Mushroom Research Division, National Institute of Horticultural & Herbal Science, RDA, 1Suwon 441-707, Korea. Department of food and nutrition, Sungshin women’s university) | Young Bok Yoo