[Investigation of a genetically determined physiological characteristic of two strains of cultivated mushrooms for its suitability as a basis for early selection following cross-breeding].

The different growth response of two strains of cultivated mushrooms (a cream-colored and a white one), on malt agar was tested to determine its suitability for selection following cross-breeding. While the white strain always grew faster on malt agar than did the cream-colored one, the progeny of each strain no longer showed this dependence on the nutrient medium. Progeny of several white mushrooms which had originated by mutation in a cream-colored strain were tested also. These mushrooms have a white cap but retain the more robust growth habit characteristic of the cream-colored strain. On malt agar they grow no faster than does the cream-colored strain. The characteristic described cannot be used as a basis for selection following crosses of cream-colored × white varieties, since cap color and mycelial growth habit are determined by different genes.