Volume 12 Part 1 Article 7: Selection of New Hybrids of Agaricus edulis (syn. A. bitorquis) Able to Differentiate Fruit Bodies at 15°C

Volume 12 Part 1 Article 7
Year 1989
Title: Selection of New Hybrids of Agaricus edulis (syn. A. bitorquis) Able to Differentiate Fruit Bodies at 15°C
Authors: J. Valjalo and J. Labarere

Abstract:

The edible mushrocm Agaricus edulis has a similar phenotype to that of the cultivated mushroom Agaricus bisporus. It is currently grown at a temperature of 25-27°C, under similar conditions to those prevailing in the growth of the Agaricus bisporus (Poppe J.A. 1972; Wood D.A. 1978).

This bipolar heterothallic fungus has tetraspored basidia, each basidiospore containig a single nuclear type (Raper C.A. 1976). Such a structure is particularly favorable to the implanentation of genetic breeding programs in , because i t allows the production of homokaryotic strains, and then, of dikaryotic strains by fusion of mycelia of different genetic origins (Fritsche G. 1974, 1981; Elliott T.J. 1978).

Due to developnental requirements, most of the wild-type strains of Agaricus edulis cannot differentiate fruit bodies at temperatures below 22°C. A breeding program was undertaken to produce, by genetic recombination, hybrid varieties able to fruit at low temperatures. The genetic stock used consisted of ten wild-type strains from different locations and biotypes.

To obtain many new homokaryotic genetic combinations and a large number of dikaryotic strains for selection, we carried out randan hybridizations by anastonosis of mycelia derived fran mixtures of germinating basidiospores. Four successive cycles of randan hybridization and selection were achieved, the selection criteria being the ability to produce fruit bodies at temperature lower than the normal fruiting tamperature.

Temperatures of 22°C, 20°C, 18°C and 15°C were successively applied during selection. Further operations in the genetic improvement process will be carried out on the hybrids selected for the production of fruit bodies at 15°C.

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