Survey of Cassava Anthracnose Disease Occurrence in Various Local Cultivars of Cassava Cultivated in Regency of Gunungkidul, Special Region of Yogyakarta

Abstract

Cassava farmers in Regency of Gunungkidul prefer to cultivate local cultivars of cassava, hence allowing the region to have a high diversity of cassava germplasm. However, improper cultivation system applied by local farmers triggered the infection of several diseases, including cassava anthracnose disease (CAD) caused by Colletotrichum sp. This study was aimed to compare the disease occurrence of CAD infecting various local cultivars of cassava cultivated in Regency of Gunungkidul. This study was carried out through survey where samples were selected using purposive sampling method. Incidence of CAD was thoroughly observed from nine local cultivars (Gatotkaca, Adira, Jawa, Ketan Putih, Ketan Merah, Gambyong, Manalagi, Kirik and Bamban) cultivated in several sub districts in Regency of Gunungkidul. Each cultivars was represented by 18 plants. Cropping system applied in all cultivars was also observed. Statistical analysis was performed using a one-way analysis of variance and the significance among cultivars was further assessed using DNMRT with a p<0.05. Results showed high incidence and severity of CAD were recorded from bitter cassava cultivars (Gatot Kaca, Kirik, Jawa, Gambyong, Bamban) where Gatot Kaca cultivar was assumed to be the most susceptible one. CAD infection in these bitter cassava cultivars was predicted to be transmitted through planting materials. The use of shady-stored stake from the previous planting season might be associated with this pathogen transmission, thus resulting in higher CAD severity.