No abstract

The influence of cultivation substrate (compost) quality as an environmental factor was determined on three traits of interest in the selection of Agaricus bisporus strains. Induced variations in compost nitrogen and copper content were used to modify compost quality. Compost effect and strain × compost interaction were found to be significant for bacterial blotch susceptibility, natural cap colour and yield. Two classes of strain not affected by compost quality were identified in a group of commercial and wild strains: white mushrooms susceptible to bacterial blotch and brown resistant mushrooms. The relation between compost composition quality and mushroom quality traits are specific for each group of strain. Nitrogen and copper content of composts were of interest as indicators of compost quality but other factors have to be evaluated for better compost characterization.

Variation of Agaricus bisporus susceptibility to bacterial blotch in relation to environment was studied at the biochemical level. Significant differences were observed between A. bisporus strains for tyrosinase and gamma-glutamyl transferase (GGT) activities and for gamma-L(+)glutaminyl-4-hydroxybenzene (GHB) content. A lower effect was detected for compost quality. GGT activity and GHB content were related to strain susceptibility to bacterial blotch by a linear model depending on strain type, commercial or wild.