Judul: Induksi variasi somaklonal dan uji in vitro untuk perbaikan ketahanan phalaenopsis terhadap penyakit busuk lunak
Abstrak: Soft rot disease caused by Erwinia carotovora subsp. carotovora is an important disease of Phalaenopsis sp. Efforts have been made to control the disease, but the results are not sufficiently promising. The use of resistant varieties is commontly recommended to control the disease because of its save impact to the environment and human life. Therefore, development of new superior varieties that are highly resistant to the disease is very urgent at the moment. Somaclonal variation using mutagenic agents is proven to be one of feasible technique to provide promising resistant varieties. In this study, development new resistant varieties to soft rot disease was conducted by using physical mutagenesis gamma ray irradiation and chemical mutagenesis EMS that were induced somaclonal variation and combined with in vitro testing technique. Gamma ray and EMS were applied separately to the calli. The treated calli were regenerated on selected in vitro medium enriched with plant growth regulator. The results showed that somaclone variation occured on the three clones treated. Frequency of occurance of somaclone variation using gamma ray variation was 0.4- 6.85 while using EMS was 0.9 – 20.8%. The all variants were in vitro tested for their resistance to soft rot disease by using pathogen suspension agent Erwinia carotovora subsp. carotovora and it was obtained 162 potential mutant resistant to soft rot. After all potential mutant resistant being tested using the same agent in the field, it was proven that of the total available genetic materials, 14 mutants of SGN-PV2.11, 6 mutants of clone No. 642 and 4 mutants of clone No. 377 were resistant to Erwinia carotovora subsp. carotovora, the cause agent of soft rot disease.
Keyword: 

Judul: Salah satu kendala dalam budidaya anggrek Phalaenopsis di daerah tropis adalah rendahnya ketahanan terhadap penyakit busuk lunak. Penyakit ini disebabkan oleh bakteri patogen Dickeya dadantii. Penggunaan varietas tahan atau resisten merupakan salah satu alternatif pengendalian yang dapat diandalkan dan merupakan salah satu solusi yang tepat untuk mengatasi kendala tersebut. Varietas tahan dapat diperoleh melalui evaluasi dan seleksi ketahanan tanaman dengan menginokulasikan penyakit, namun seleksi ketahanan bukan sesuatu hal yang mudah dilakukan karena terkait dengan penyebaran dan penularan penyakit serta membutuhkan waktu yang lama dalam seleksi. Cara yang digunakan untuk mengatasinya adalah penggunaan marka molekuler, yang dapat mempersingkat waktu seleksi dalam memperoleh tanaman yang resisten. Serangkaian kegiatan penelitian dilakukan untuk mengembangkan metode evaluasi respon ketahanan anggrek Phalaenopsis terhadap infeksi bakteri D. dadantii, mengevaluasi respon ketahanan genotipe anggrek Phalaenopsis terhadap infeksi D. dadantii, mengisolasi dan mengkarakterisasi gen Pto asal 20 genotipe anggrek Phalaenopsis, dan mengembangkan marka SNAP (Single Nucleotide Amplified Polymorphism) pada 32 genotipe anggrek Phalaenopsis berbasis gen Pto.
Abstrak: Salah satu kendala dalam budidaya anggrek Phalaenopsis di daerah tropis adalah rendahnya ketahanan terhadap penyakit busuk lunak. Penyakit ini disebabkan oleh bakteri patogen Dickeya dadantii. Penggunaan varietas tahan atau resisten merupakan salah satu alternatif pengendalian yang dapat diandalkan dan merupakan salah satu solusi yang tepat untuk mengatasi kendala tersebut. Varietas tahan dapat diperoleh melalui evaluasi dan seleksi ketahanan tanaman dengan menginokulasikan penyakit, namun seleksi ketahanan bukan sesuatu hal yang mudah dilakukan karena terkait dengan penyebaran dan penularan penyakit serta membutuhkan waktu yang lama dalam seleksi. Cara yang digunakan untuk mengatasinya adalah penggunaan marka molekuler, yang dapat mempersingkat waktu seleksi dalam memperoleh tanaman yang resisten. Serangkaian kegiatan penelitian dilakukan untuk mengembangkan metode evaluasi respon ketahanan anggrek Phalaenopsis terhadap infeksi bakteri D. dadantii, mengevaluasi respon ketahanan genotipe anggrek Phalaenopsis terhadap infeksi D. dadantii, mengisolasi dan mengkarakterisasi gen Pto asal 20 genotipe anggrek Phalaenopsis, dan mengembangkan marka SNAP (Single Nucleotide Amplified Polymorphism) pada 32 genotipe anggrek Phalaenopsis berbasis gen Pto., One of the obstacles in a Phalaenopsis orchid cultivation in tropical regions is the low resistance to soft rot disease. The disease is caused by pathogenic bacteria Dickeya dadantii. Using resistant varieties is one of alternative control to do and is one of the appropriate solutions to overcome these obstacles. Resistant varieties can be obtained through the evaluation and selection of plant resistance by inoculating disease, but is not an easy thing to do because it can spread and transmission the disease and requires long time in the selection. Using molecular markers could shorten the time of selection to obtain resistant plants. A series of research activities were carried out to developed evaluation method of Phalaenopsis orchid resistance response to bacterial infections D. dadantii, evaluated respons of Phalaenopsis resistance to infection D. dadantii, isolated and characterized the Pto gene from 20 genotypes Phalaenopsis, and developed SNAP markers in 32 genotypes Phalaenopsis based on Pto gene.
Keyword: Soft rot, Disease resistance, Pto gene, Molecular markers, SNAP, Plant resistance, Genetic diversity, Gene

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.
Keyword: