Judul: Perbandingan Nilai Tengah Nomor Somaklon Jahe (Zingiber officinale Rosc.) dengan Menggunakan Uji Lanjut Scott-Knott
Abstrak: Ginger (Zingiber officinale Rosc.) is a herb plant used for herbal medicine, food and drink ingredient. Major obstacle that has been disrupting ginger production is bacterial wilt disease. Efforts are most effective and efficient to solve these problem is using tolerant varieties. Balai Penelitian Tanaman Rempah dan Obat (Balittro) as a research institution of spices and medical plants has been doing a research to obtain tolerant varieties. Tolerant varieties were obtained from ginger’s somaclones which tolerant to bacterial wilt disease. Five somaclone populations, FA, FB, AC1, AC2, and Fipla were tested the resistance to bacterial wilt disease. Research conducted on three response variables, namely the intensity of the disease, the appearance of the plants index (IPT) of growth variables, and IPT of production variables. The objectives of this study were to group the treatment means of ginger’s somaclones number with Scott-Knott test and to identify the characteristics of the three response variables. Scott-Knott test further showed red ginger’s number (CJ2.8B) is the most tolerant to bacterial wilt disease by the percentage intensity mean 19.65%. Ginger’s somaclone number AC1.39B has the best growth with mean IPT of growth variables 12.99. Ginger’s somaclone number AC1.19B has the highest productivity with mean IPT of production variables 18.36. Based on the classification of three grouping response variables, AC1.19B is the best and tolerant ginger somaclone number.
Keyword: Scott-Knott test, intensity of bacterial wilt disease, ginger’s somaclone number, appearance of the plants index (IPT)

Judul: Endophytic bacteria as alternatives diseases control of bacterial wilt on ginger (Zingiber officinale).
Abstrak: Ginger is cultivated in many tropical and subtropical regions of the world. Growers expressed concern regarding the impact of pathogens on yields in recent years. Similarly, growers expressed concern regarding the effect that pathogen threats will have on the industry in the future. Bacterial wilt disease caused by Ralstonia solanacearum is an important disease on ginger plant (Zingiber officinale Rosc) in Indonesia. The objective of this research was to study the effectiveness of endophytic bacteria in inhibiting the progress of bacterial wilt disease on ginger. Three isolates of endophytic bacteria were selected and tested their antibiosis activity and plant growth promoting rhizobacteria (PGPR) against the bacterial wilt disease (R. solanacearum). The research showed that under greenhouse condition all of the ginger plants treated with the 3 isolates of endophytic bacteria produced symptoms of bacterial wilt disease 7 days after inoculation of R. solanacearum. The 3 isolates of can only inhibit 12 % of severity of bacterial wilt disease on ginger up to 42 days after the inoculation, therefore they are not effective as biocontrol agent.
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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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