The mushroom cultivator. A practical guide to growing mushrooms at home

Paul Stamets. The mushroom cultivator. A practical guide to growing mushrooms at home. - Agarikon press, 1983

Содержание

FOREWORD by Dr. Andrew Weil

PREFACE

I. INTRODUCTION TO MUSHROOM CULTURE

II. STERILE TECHNIQUE AND AGAR CULTURE

III. GRAIN CULTURE

IV. THE MUSHROOM GROWING ROOM

V. COMPOST PREPARATION

VI. NON-COMPOSTED SUBSTRATES

VII. SPAWNING AND SPAWN RUNNING IN BULK SUBSTRATES

VIII. THE CASING LAYER

IX. STRATEGIES FOR MUSHROOM FORMATION (PINHEAD INITIATION)

X. ENVIRONMENTAL FACTORS: SUSTAINING THE MUSHROOM CROP

XL GROWING PARAMETERS FOR VARIOUS MUSHROOM SPECIES

XII. CULTIVATION PROBLEMS AND THEIR SOLUTIONS: A TROUBLESHOOTING GUIDE

XIII. THE CONTAMINANTS OF MUSHROOM CULTURE: IDENTIFICATION AND CONTROL

XIV. THE PESTS OF MUSHROOM CULTURE

XV. MUSHROOM GENETICS

APPENDICES

GLOSSARY

BIBLIOGRAPHY

INDEX

PHOTOGRAPHY AND ILLUSTRATION CREDITS

ACKNOWLEDGEMENTS

OCR
338/Mushroom Genetics
There are two types of homothallism in mushrooms: primary and secondary. Primary
homothallism is the case described above, where the majority of spores, while initially forming
monokaryotic colonies, will eventually become dikaryotic and fruit normally. Secondary homothallism is the case where each spore receives one nucleus of each mating type, generating a dikaryotic
colony from the moment of spore germination. Agaricus brunnescens is the best known example
of this type of fungus, while another commonly cultivated mushroom, Volvariella volvacea, has a
primary homothallic mating system.

IMPLICATIONS FOR CULTURE WORK
The single most important implication of the genetics that has been described thus far is the oc-

currence of illegitimate matings. In a tetrapolar fungus, only one fourth of the spores from any one
mushroom are fully compatible with any random spore from that same strain. This mechanism exists to encourage outcrossing. When a cultivator is trying to produce a strain from a spore print, establishing a fruiting strain can be frustrating. This is because monkaryotic hyphae with common A
factors or with common B factors can fuse and form dikaryons, and these dikaryons can even
make convincing looking clamp connections. (See Figs. 1 0 and 1 82). These colonies, however,
are incapable of fruiting. It becomes obvious at this point that two thirds of the random dikaryons
formed will be of the illegitimate type. This implies that a large number of dikaryotic cultures must
be isolated and tested for fruiting ability. Another, but less precise way around this problem is to
inoculate with a large number of spores and take a tissue culture of the first mushroom that appears
in the culture. This procedure is the one usually listed in books on mushroom cultivation because it
is simple, but the strains produced in this manner still must be tested thoroughly.
The phenomenon of sectoring is the production of wedge shaped areas of differing physical
or growth characteristics by a colony of mycelium. There are two types of sectoring, one found in

young cultures, and one in old ones.
In young multispore cultures, several different strains are all growing together at the same time.
Some are the products of legitimate matings, some of illegitimate ones. These strains all have differing characteristics. Some of these strains grow faster than others, some are rhizomorphic and some
are fluffy in appearance. Some fruit well, some poorly. Some produce clumps of many tiny mushrooms, some produce a few large ones. They each have a unique set of preferred culture conditions.
Fortunately, the different strains formed from multispore germinations tend to sort themselves
out. As the colony grows, strains segregate into sectors of different appearances and growth rates.
The repeated separation and propagation of individual sectors, until a colony is obtained which no
longer produces new ones is one way of isolating a pure strain. Several strains may be isolated from
the same original petri plate in this way.
As pure cultures grow old and become senescent, they produce ever greater quantities of sectors due to the accumulation of random mutations. Repeated subculturing of the culture gives accumulated mutations a chance to express themselves. A strain which has reached this condition is no

longer pure, and should not be used for cultivation.

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