<![CDATA[One of the key factors for successful oyster mushroom cultivation is the use of superior spawn. However, mushroom farmers in the Karawang region face challenges in obtaining affordable and high-quality spawn. To address this issue, efforts have been made to provide superior spawn to oyster mushroom cultivators in Karawang. In a study conducted in Karawang, researchers crossed two parental strains of oyster mushrooms: one from Cilamaya Kulon (white oyster mushroom) and the other semi-wild strain from Purwasari. This crossbreeding resulted in several candidate spawn isolates (G5 Faperta Unsika) with desirable traits inherited from both parent strains. The goal was to identify the best-performing isolate for spawn production. The research was carried out in a 6.5 m x 4 m mushroom house in Dusun Pasir Buah, Desa Pasir Mulya, Kecamatan Majalaya, Kabupaten Karawang. Over a period of 2 months (from April to May 2024), six different spawn isolates were compared: A (G5 FP Semi), B (G5 FP Putih), C (G5 FP001), D (G5 FP010), E (G5 FP024), and F (G5 FP039). Each treatment was replicated five times. The results showed that treatment B (G5 FP Putih) performed the best, with an average harvest weight per tray of 1237.36 g and a total yield of 89.09 kg per mushroom house. Isolate F (G5 FP039) also performed well, with an average harvest weight of 1212.12 g per tray and a yield of 87.27 kg per mushroom house. Therefore, isolate FP039 is recommended as a superior spawn for oyster mushroom cultivation in Karawang Keywords: straw mushroom, spreading seeds, G5 Faperta Unsika isolate]]>
