DIFFERENCES IN SUSCEPTIBILITY OF AGARICUS-BISPORUS STRAINS TO BACTERIAL BLOTCH AND IN NATURAL CAP COLOR RELATED TO COMPOST COMPOSITION

The influence of cultivation substrate (compost) quality as an environ mental factor was determined on three traits of interest in the select ion of Agaricus bisporus strains. Induced variations in compost nitrog en and copper content were used to modify compost quality. Compost eff ect and strain x compost interaction were found to be significant for bacterial blotch susceptibility, natural cap colour and yield. Two cla sses of strain not affected by compost quality were identified in a gr oup of commercial and wild strains: white mushrooms susceptible to bac terial blotch and brown resistant mushrooms. The relation between comp ost composition quality and mushroom quality traits are specific for e ach group of strain. Nitrogen and copper content of composts were of i nterest as indicators of compost quality but other factors have to be evaluated for better compost characterization.