Agaricus brunnescens

Another alternative is to continuously experiment with the creation of hybrid strains that are formed from the mating of dikaryotic mycelia of Two genetically distinct parents, (experimentswith Agaricus brunnescens have shown, however, that most hybrids yield than both or one of the contributing strains. A minority of the hybrids resulted in more reductive strains.)... 

Mushroom spawn is used to inoculate prepared substrates. This inoculum consists of a carrier material fully colonized by mushroom mycelium. The type of carrier varies according to the mushroom species cultivated, although rye grain is the choice of most spavwi makers. The history of the development of mushroom spawn ior Agaricus brunnescens culture illustrates how spawn production has progressed in the last hundred years. 

A maximum number of air exchanges/hour for Agaricus brunnescens is 4-6. 

Figure 119 Growth curve of Agaricus brunnescens on compost.

Figure 127 Mycelial growth (Agaricus brunnescens) into casing with optimum moisture.

Figure 131 Cased grain culture of Agaricus brunnescens showing overlay and stroma.

Figure 132, 133 134 Three day pinhead development sequence in Agaricus brunnescens. Change-over from Stage III to Stage IV occurs within this time frame.

Figure 137 Agaricus brunnescens affected by high CO2 concentration. Note iong stems and underdeveloped caps.

Because many mushrooms are sensitive to carbon dioxide, the physical development of the mushroom can also be used as a guide. High CO2 environments produce long stems and small underdeveloped caps in Agaricus brunnescens and Pleurotus ostreatus. Pleurotus exhibits similar symptoms in conditions of low light intensity. 

Nutritional Content Thought to be similar to Agaricus brunnescens. 

Figure 146 Agaricus brunnescens fruiting in trays of compost.

Figure 145a Agaricus brunnescens fruiting on cased rye grain spawn.

Figure 145b Characteristic Agaricus brunnescens mycelium.

History, Use and/or Medical Implications Some species pathogenic to humans. Of special note is Pseudomonas aeruginosa (also known as Ps. pyocyanea). a species that causes blindness and other diseases. Pseudomonas putida is stimulatory to primordia formation in certain strains of Agaricus brunnescens (bisporus) and its use is of potential commercial value. 

Figure 230 Red Pepper Mites swarming on Agaricus brunnescens.

Discussion Tarsonemusm Aes are very small, 180-190 microns long, with pale brown, shining, oval bodies. They occasionally swarm in masses on mushroom caps but otherwise are rarely seen except by microscopic examination. Females produce an average of 22 eggs in a lifetime of 2-8 weeks. These mites cause a bright reddish-brown discoloration at the base of the mushroom stem and may cut the stem s mycelial connections. Known to survive normal compost pasteurization temperatures, they can carry a virus disease to Agaricus brunnescens. 

The results of Urayama s work showed that each of the four fractionations induced primordia formation provided aqueous methanol (80%) and only young mushrooms were used. Extractsfrom older fruitbodies, especially that oi Agaricus brunnescens and Lentinus edodes, had no effect whatsoever. Urayama tried other solvents to isolate the mysterious fruiting hormone" and discovered that it was soluble in water and not soluble in absolute methanol, chloroform or petroleum benzine. He worked on his "Substance X", as he liked to call it, for many years until his death in 1980. 

Wood (1 979) tried to substantiate the findings of Lino and Ishikawa with Agaricus brunnescens and failed. He could not induce primordia to form using c AMP. However, this fact does not bear any significance on the importance of cyclic adenosine monophosphate in phototropic species since A. brunnescens is a mushroom needing no light whatsoever for primordia formation and development. 

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