The button mushroom (Agaricus bisporus) is one of the most widely cultivated important edible mushroom species. In the breeding of new button mushroom, ‘Seolgang’ was developed by crossing two monokaryons ‘CM020913-27’ and ‘SSU423-31’. Because of the secondarily homothallism, only a small percentage of the basidia produce 3 or 4 spores, which are mostly haploid (n) and do not fruit. Single spore cultures derived from these types of spores produce a vegetative mycelium that also contain a variable number of genetically identical nuclei per cell called monokaryon. The lack of clamp connections between monokaryon and dikaryon required a series of mycelial culture and fruiting test. After crossing, hybrids were cultivated on a small scale and on a commercial scale at a farm. For this, the spawn was made by a commercial spawn producer and the spawned compost by a commercial compost producer. Mycelial growth of ‘Seolgang’ on CDA was better at 20℃ and 25℃ when it was compared with that of ‘505 Ho’. The mature cap shape of new strain ‘Seolgang’ is oblate spheroid and the immature cap shape is round to oblate spheroid. The cap diameter was 41.2 mm on average. In comparison with white strain ‘505 Ho’, the strain had a yield that was 9% higher. It produced fruiting bodies which had a higher weight on average per fruiting body and were 19% firmer with a good shelf life. Days of fruiting body were 3-4 days later than those of ‘505 Ho’. The physical characteristics such as elasticity, chewiness, adhesiveness were better than that of ‘505 Ho’. Genetic analysis of the new strain ‘Seolgang’ showed different profiles compared to ‘505 Ho’, CM02913-27, SSU413-31, when RAPD primers A02 and O04 were used.

ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
  Single basidiospore isolates and monokaryons
  Media and culture.
  Fruiting trial
  Determination of color value
  Nutrient content determination
  Texture profile analysis
  DNA preparation
  DNA polymorphic analysis
 RESULT AND DISCUSSION
 REFERENCES

• Byung-Joo Lee(Crop Research Division, Chungcheongnam-do Agricultural Research & Extension Services, Yesan 340-861, Korea)
• Mi-Ae Lee( Crop Research Division, Chungcheongnam-do Agricultural Research & Extension Services, Yesan 340-861, Korea) | Mi-Ae Lee
• Yong-Gyun Kim( 1Crop Research Division, Chungcheongnam-do Agricultural Research & Extension Services, Yesan 340-861, Korea) | Yong-Gyun Kim
• Kwang-Won Lee( 1Crop Research Division, Chungcheongnam-do Agricultural Research & Extension Services, Yesan 340-861, Korea) | Kwang-Won Lee
• Yong-Pyo Lim( Department of Horticultural Science, Chungnam National University, Daejeon 305-764, Korea) | Yong-Pyo Lim
• Byung-Eui Lee( Industry Academy Cooperation Foundation, Soonchunghyang University, Asan 336-745, Korea) | Byung-Eui Lee
• Ho-Yeon Song( College of Medicine, Soonchunghyang University, Chunan 330-930, Korea) | Ho-Yeon Song