Judul: Identifikasi Xanthomonas oryzae pv. oryzae dengan Teknik Biomolekuler dan Karakter Patogenitas terhadap Padi Galur Isogenik.
Abstrak: Increased production of paddy can face obstacle because the biotic stresses like bacterial leaf blight (BLB). The aim of this research to identification BLB caused by Xanthomonas oryzae pv oryzae (Xoo) by biomolecular technique using three primers specific Xoo through PCR colony, and to know virulence of Xoo isolates from West Java, West Sumatera, West Borneo by clip method for character of pathogenicity analysis using near-Isogenic lines and popular varieties. The purifying result were obtained 72 isolates namely 20 isolates from West Java, 30 isolates from West Sumatera, 22 isolates from West Borneo. Most of isolates were identified Xoo positive, except isolate Xoo11-023 from West Sumatera were identified Xoo negative. The character of pathogenicity showed that Code which contain resistant gene Xa4-Xa7 and IRBB5 which contain resistant gene xa5 were resistant to Xoo from all three areas. The average disease intensity on Code and IRBB5 of isolates from West Java was 1.62 % and 3.55%, West Sumatera was 2.10 % and 2.97 %, West Borneo was 2.17 % and 4.45 %. Isolate Xoo11-042 from West Sumatera was the one having highest virulence with average disease intensity on Code 3.29 % and IRBB5 6.90 % which classified as moderate resistant.
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Judul: Asosiasi Aktivitas Selulolitik dan Analisis Molekuler dengan Metode Rep-PCR dari Xanthomonas oryzae pv. oryzae
Abstrak: Xanthomonas oryzae pv. oryzae (Xoo) causes bacterial leaf blight (BLB) of rice. Twenty seven Xoo from several regions in Indonesia were tested cellulolytic activity with CMC media, molecular analysis were analyzed using the technique of Rep-PCR, and analyzed the association between the two by using the program Tassel. The purpose of this study is to investigate the association between cellulolytic activity and molecular analysist with Rep-PCR method from Xoo DNA bacteria. The results of cellulolytic activity from 27 isolates Xoo, 7624 isolate known as type IV has the largest clear zone is 1.43 cm and Xoo12-253 isolate has the smallest clear zone is 0.31 cm. For the molecular characteristics, used BOXA1R, (GTG)5, and ERIC primers to amplify genomic DNA and produces polymorphic Xoo DNA bands different between three primers. Most PIC value obtained by the ERIC primer with value 0.34. The results of testing the association of cellulolytic activity and molecular characteristics of DNA amplification by Rep-PCR were known that have a low correlation and no significant association between the two
Keyword: Bogor Agricultural University (IPB), Xanthomonas oryzae, Rep-PCR, molecular analysis, cellulolytic

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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