Introduction
Mushrooms are a very large group of organisms. The number of species of mushrooms is estimated at 1.5 million, of which about 300 are edible, only 30 have been domesticated, and finally 10 species are cultivated commercially. Oyster mushrooms (Pleurotus spp.) of the genus Pleurotus are the most important cultivated edible mushrooms in the world after button mushrooms. Edible mushrooms are now considered one of the most important food sources in the world, and their cultivation is constantly increasing with population growth. For this reason, the importance of cultivating edible mushrooms is increasing day by day. In edible mushrooms, the mycelium that emerges from a single spore is sterile and requires hybridization between compatible monokaryotic mycelia to complete the sexual cycle. The oyster mushroom P. eryngii has also been given the name of king oyster mushroom due to its large edible organ. The mushrooms grow in small groups. The spores of this mushroom are white, and its mycelium has a connecting arch. The king oyster mushroom has a firm texture and short radial blades.

Materials and Methods
In this study, three species of oyster mushrooms (Pleurotus ostratus var florida, P. eryngii, P. corncopia) were crossed with each other in order to benefit from the special characteristics of each species and their aggregation into one species. Monokaryons of each species were prepared. Then, monokaryons of the two species were placed 5 mm from each other. For the cultivation of hybrid spawn and parents, three beds containing wheat straw (weighing 6.8 kg) were prepared for each and sterilized. After spawning, the beds were placed in a suitable environment and then the humidity of the environment was increased to 85-90% until the hybrids started to produce primary nodes and then pin and turn into mature heads. The heads at this stage were tested for spore production.

Results and Discussion
The results showed that from 300 crosses, only in 4 crosses did the Florida and eryngii monokaryons grow together and form a clamp connection, producing dikaryons, and four hybrids named H₁, H₄₀, H₁₁, and H₃₂ were obtained. While from among 300 crosses between Florida monokaryons and yellow fungus and 100 crosses between eryngii monokaryons and yellow fungus, no dikaryons were produced due to interspecific incompatibility. Spawns of the produced hybrids were prepared with Florida and eryngii and then cultivated in sterile media in a completely randomized design with three replications. The average base diameter of eryngii was significantly greater than that of Florida. The average base diameter of eryngii was not significantly different from that of the H₁₁ hybrid, while the average base diameter of eryngii was greater than that of the H₃₂ and H₁₁ hybrids and less than that of the H₁ hybrid. There was also a significant difference in the average base diameter among the hybrids. Among the hybrids, H₁ had a larger average base diameter than that of the H₄₀, H₃₂, and H₁₁ hybrids. eryngii had the highest fresh weight of edible organs with an average fresh weight of 120.5 grams. The average fresh weight of edible organs of eryngii was not significantly different from that of hybrid H₄₀. In terms of yield (fresh and dry weight), the hybrids H₁₁, H₁ and H₃₂ were very similar and were placed in a single cluster. On the other hand, the hybrid H₄₀ was similar to eryngii. In general, the hybrids and eryngii were placed in the same group in terms of yield. This is while Florida occupied a separate group. The result is that in terms of yield, the hybrids were similar to eryngii and the high yield traits from Florida were not transferred to the hybrids.

Conclusion
There was a significant difference between genotypes in terms of spawn running, and the hybrids were similar to eryngii and spawn running for a longer period than Florida. Hybrids H₄₀ and H₃₂ were earlier than their parents and other hybrids because they had shorter days to first pin emergence and ultimately shorter planting period. Hybrid H₄₀ is considered a suitable hybrid with similar edible organ fresh weight to eryngii. Hybrid H₄₀ had higher yield (fresh weight) and biomass than other hybrids and was similar to eryngii. The least sporulation (spore germination) was observed in hybrids H₁ and H₁₁, which was even lower than eryngii. Hybrid H₄₀, although it seems to be a desirable hybrid in some traits, had high spore germination and was similar to Florida.