EVALUASI KETAHANAN KLON HARAPAN UBIKAYU (Manihot esculanta Cranz.)TERHADAP PENYAKIT LAYU DAN BUSUK UMBI

Abstract

In cultivation of cassava (Manihot esculanta Cranz.) several disease symptoms including wilt and tuber rot caused by a fungus Fusarium sp. is a contstraint reducing the quantity and quality of tuber production. The use of disease-resistant clones is an efficient and practical means for disease control. The trials were conducted in greenhouse and laboratory of ILETRI (Indomesian Legumes and Tuber Crops Research Institute) at Malang. Seven cassava clones were evaluated for disease resistantce. In greenhose, the cassava staks were planted in sterile soil in plactic bags (volume of 5-6kg). Before plnting, the plant materials were inoculated by dipping methods for 30 minutes in Fusarium spores suspension (at concentration 10⁶ spores/ml). In laboratory, the fresh cassava roots were sliced then inoculated by slices inoculation method. A result of greenhouse trial is the wilt symptom firstly observed in 30 till 41 days after planting. Among seven clones tested, five clones were categorized resistant CMM 02048-6, Adira-4, MLG 10311, OMM9908-4, and Malang-1. In laboratory trial, two clones including MLG 10311 and CMM 02048-6 were categorized tolerant, and a high resistant clone is Malang-1. The resistant clones must be tested in field under different ecological areas especially in endemic areas for natural resistance confirmation