Resources of Pleurotus ostreatus and Pleurotus eryngii in Greece: perspectives for cultivation and mushroom production

During the last five years an inventory of the species Pleurotus ostreatus and Pleurotus eryngii has been made in different regions in Greece, kindly supported by some local amateurs. The collection in our laboratory is made up of numerous strains isolated by tissue culture from wild fruit bodies: over 100 for P. ostreatus and about 40 for P. eryngii. In a previous study an approach of the biodiversity was achieved by analyzing allelic polymorphism at mating type loci in a sample of P. ostreatus isolates, that made evident the variability likely to exist in this biological material. As the further goal of our laboratory is breeding work for commercial strains, a great part of this material has been studied for some physiological characteristics, which are related to the fitness of the isolates for colonizing lignocellulosic substrates and producing fruit bodies. The growth rate on a PDA culture medium was assessed at different temperatures as well as the velocity of the linear colonization of wheat straw conveniently treated in hot water. Furthermore, their behavior in culture conditions was followed mainly regarding the maximum temperature that permits the fruit-bodies initiation and mushroom production. The sporocarp morphology was also taken into account as it presents economical interest, especially concerning the foot length and the cap color. These studies revealed a large diversity in our material and allowed us to apply a first screening regarding the considered traits. The point that must be noticed is the abundance of wild isolates able to fructify at relatively high temperature, around 26oC for P. ostreatus and 20oC for P. eryngii, which is very important for Pleurotus cultivation in hot climates during the summer. Apart from these results knowledge was also acquired, concerning the exclusive use of wheat straw, treated only by dipping it for a short time in hot water, for Pleurotus cultivation on a commercial scale.