Judul: The Inheritance of tungro resistance in rice selection CR94-13 and allelic relationships of genes for tungro resistance in CR94-13 and IR833-6-2-1 lines
Abstrak: Inheritance of resistance to tungro virus was investigated in rice selection CR94-13 which is highly resistant to tungro. Allelic relationships of genes for resistance in CR94-13 and IR833-6-2-1 another resistant selection were also studied. F1, F2, F3 populations from the crosses CR94-13 x IR1416-131-5 and IR833-6-2-1 x CR94-13 were screened under heavy disease pressure under field conditions in South Sulawesi, Indonesia. The results indicated that two pairs of incompletely dominant genes conveyed resistance to tungro in CR94-13. In addition to the two pairs of incomplete...
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Judul: Tungro Disease in Indonesia: detection, genetic variability, and suitability map of tungro resistant varieties
Abstrak: Penyakit tungro, yang disebabkan oleh infeksi Rice tungro bacilliform virus (RTBV) dan Rice tungro spherical virus (RTSV), masih merupakan salah satu penyakit penting pada tanaman padi di Indonesia. Selain itu, penyakit yang ditularkan oleh wereng hijau secara semipersisten ini masih menjadi salah satu faktor pembatas peningkatan produksi. Kerugian yang diakibatkan oleh penyakit ini pada stadia awal pertumbuhan padi mampu menyebabkan kehilangan hasil hingga 90%, dan tak jarang menyebabkan tanaman menjadi puso. Hingga saat ini penyakit tungro dilaporkan telah menyerang pertanaman padi di 27 propinsi dengan luas serangan penyakit selama tahun 2012 mencapai 6441 ha dan puso 151 ha. Penggunaan varietas tahan merupakan salah satu teknik pengendalian yang efektif. Namun kurangnya jumlah varietas tahan tungro spesifik lokasi yang sesuai dengan preferensi petani, menyebabkan aplikasi di lapangan agak sulit dilakukan. Selain itu, informasi keragaman genetika virus tungro, khususnya isolat Indonesia, masih sangat terbatas. Berdasarkan hal tersebut perlu dipelajari faktorfaktor yang memengaruhi keberadaan penyakit tungro di lapangan, dan informasi mengenai keragaman genetika virus tungro yang sangat penting dalam pengembangan strategi pengendalian virus tungro. Pengembangan teknik deteksi cepat dan akurat perlu dilakukan untuk memudahkan pengambilan keputusan pengendalian penyakit di lapangan. Survei yang dilakukan di beberapa lokasi pertanaman padi di Indonesia menunjukkan bahwa penyakit tungro masih menjadi penyakit penting. Penyakit tungro telah meluas terutama di sentra produksi padi. Penyebaran virus tungro sangat bergantung pada jenis varietas yang dibudidayakan, pola tanam, keberadaan serangga vektor dan sumber inokulum, serta pengelolaan budidaya tanaman padi. Hasil survei menunjukkan spesies gulma yang ditemukan di sekitar persawahan di beberapa lokasi di Jawa Barat, Bali, Nusa Tenggara Barat, Sulawesi Selatan, Sulawesi Barat, Sulawesi Utara, dan Sumatera Selatan berperan menjadi inang alternatif virus tungro. Infeksi RTBV berhasil dideteksi dari enam spesies gulma (F miliacea, C. iria, M vagina/is, L. octovalvis, S. zeylanica, D. sanguinalis, dan E. crusgalli), dan infeksi RTSV berhasil dideteksi dari tiga spesies gulma (F miliacea, L. octovalvis, dan D. sanguinalis). Sanitasi gulma sebelum bertanam padi dinilai sebagai tindakan yang diperlukan dalam pengendalian penyakit tungro., Tungro disease, caused by double infection of Rice tungro bacilliform virus (RTBV) and Rice tungro spherical virus (RTSV), is still considered as an important rice disease in Indonesia. Rice production is affected by this disease, yield loss caused by infection of this viruses in the early stages ofrice growth may even reach 90%. Disease spread is dependent on its insect vector, green leafhopper, by semipersistent manner. Distribution of this disease in Indonesia is reported from 27 provinces with affected area of 6441 ha and 151 hapuso in 2012. The use of resistant varieties is one of the effective management techniques. However, the number of site-specific tungro resistant varieties that suitable with the farmer preferences still limited, so applications in the field is rather difficult to do. In addition, knowledge on genetic variability of tungro virus in Indonesia is very limited. Therefore, it becomes necessary to study all factors influencing the incidence of tungro virus in the field, and information on genetic variability of tungro virus in order to develop disease management strategy. Improvement on detection method of tungro virus also required to assist controlling the disease. Tungro disease
Keyword: Full length genome, LAMP PCR, Rice tungro virus, Strategy of management, Weeds, Rice Production, Disease Management, Tungro virus, virus detection, Serelogical Methods, Weed Species, Virus Inoculum

Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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