Penelitian ini bertujuan mengetahui variasi genetik jamur Lentinula edodes asal Malang, Cianjur, Lembang, dan Yogyakarta serta mendapatkan primer terseleksi untuk identifikasi L. edodes secara molekular. Penelitian dilakukan di Laboratorium Genetika, Fakultas Biologi, Universitas Gadjah Mada, Yogyakarta. Tahapan penelitian terdiri atas ekstraksi DNA dari miselium empat isolat L. edodes dan satu sampel outgroup (Pleurotus ostreatus), amplifikasi DNA dengan teknik PCR-RAPD menggunakan delapan jenis primer (OPA 1, OPA 2, OPA 3, OPA 4, OPA 7, OPA 8, OPA 9 dan OPA 10), elektroforesis menggunakan gel agarosa dan pengamatan pita DNA dengan UV transluminator. Data pita DNA dianalisis dengan software NTSYSpc21 untuk menentukan tingkat similaritas, jarak genetik dan untuk mengkonstruksi dendrogram berdasarkan metode UPGMA. Hasil penelitian menunjukkan bahwa semua primer yang digunakan dapat mengamplifikasi DNA sampel dan satu diantaranya (OPA 4) tidak dapat menunjukkan adanya polimorfisme pada keempat isolat. Ukuran fragmen DNA teramplifikasi berkisar antara 1291774 bp. Berdasarkan hasil penelitian dapat disimpulkan bahwa antara isolat L. edodes asal Malang, Cianjur, Lembang dan Yogyakarta terdapat variasi genetik dengan jarak genetik antara 7886%. Polimorfisme tertinggi (83,33%) diperoleh menggunakan primer OPA 2.

Dried cassava is a suitable host for the growth and development of the genus Aspergillus. Fungi reported to grow on dried cassava were A. clavatus, A. flavus, A. foetidus, A. fumigatus, A. niger, A. ochraceus, A. oryzae, A. tamarii, A. zonatus, dan Aspergillus sp. From those species, A. flavus is the most important species because of its toxigenic characteristic on agricultural product. This study was conducted to study dominant species of Aspergillus causing the most severe deterioration on stored dried cassava and causing the highest deterioration in dried cassava. The isolates were then cultured for determination of dominant species. The in vitro experiment was to obtain the species of Aspergillus that is resulted in highest change of dried cassava spoilage. Based on relative index frequency (Rif) and presence index of the fungus (Pif), A. flavus was the most dominant species and causing the highest deterioration on the dried cassava.

The effect of relative humidity and temperatur to glucoamylase activity of Aspergillus flavus on storage disease of dried cassava.  Aspergillus flavus is the most important species because of its toxigenic caracteristic on agricultural product. Among several Aspergillus species growing on dried cassava. This study was conducted to show the role of glucoamylase produced by Aspergillus flavus fowards the storage disease of dried  cassava. The effect of RH and storage room temperature to glucoamylase activity was evaluated for 4 months using Randomized Completely Block Design (Factorial). Variables observed were glucoamylase activity and starch content of dried cassava. Glucoamylase activity could be used as an early indicator of the infestation of dried cassava by Aspergillus while the change of dried cassava color had not been visible. Starch content of dried cassava decreased during the storage. Due to the glucoamylase activity of A. flavus which  degrading starch into glucose. The interaction effect of RH and storage room temperature to glucoamylase activity of A. flavus was significant.