Judul: Introduction Gene of Submergence-Tolerant (Sub1) on Ciherang Rice Varieties.
Abstrak: Upaya untuk meningkatkan produksi padi terus dilakukan seiring dengan bertambahnya penduduk dan meningkatnya kebutuhan beras. Perubahan iklim yang tidak menentu menuntut perlunya pengembangan padi yang toleran terhadap cekaman abiotik, seperti kekeringan, salinitas tinggi, maupun genangan. Hasil panen rendah dan resiko kegagalan tanam akibat banjir umum ditemui pada areal rawa pasang surut, rawa lebak, dan tepian sungai. Salah satu solusi yang berkelanjutan dan permanen adalah mengembangkan varietas dengan hasil tinggi yang toleran terhadap rendaman. Penelitian ini mengembangkan padi Ciherang toleran genangan yang dilakukan secara spesifik dengan metode persilangan terarah (site-directed crossing) untuk menghindari produk transgenik. Penelitian ini bertujuan memperoleh tanaman BC3F1 Ciherang-Sub1 hasil persilangan balik BC2F1 Ciherang-Sub1 dan Ciherang serta menyeleksi tanaman BC3F1 yang membawa gen Sub1 dengan menggunakan PCR. Hasil uji genangan diperoleh 13 tanaman BC3F1 yaitu 6 tanaman BC3F1 Ciherang/Swarna-Sub1 dan 7 tanaman BC3F1 Ciherang/IR64-Sub1. Hasil PCR dengan marka AEX1F dan AEX1R menunjukkan pita DNA untuk gen Sub1A yang berukuran 231 bp. Sedangkan hasil PCR dengan marka gabungan RM219F dan AEX1R dapat membedakan sifat heterozigot antara padi host Ciherang, donor Swarna-Sub1 dan IR64-Sub1, serta progeni BC3F1 Ciherang-Sub1 dengan tambahan pita yang menunjukkan penyisipan Sub1 dari donor ke dalam host.
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Judul: Identifikasi dan Karakterisasi Gen Toleran Genangan Populasi Padi BC4F1 Ciherang-Sub1
Abstrak: Submergence stress is one of the inhibitor factor at rice productivity. Therefore, in order to improve food security, the rice of submergence-tolerant need to be developed. Introduction of gene related to submergence-tolerant (Sub1) was done by site-directed crossing between Ciherang rice as host with rice IR64-Sub1 and Swarna-Sub1 as Sub1 donor. The aim of this study was to identify and characterize BC4F1 Ciherang-Sub1 that resulted from backcross between BC3F1 Ciherang-Sub1 and Ciherang. The existence of Sub1 gene was detected by using PCR analysis based on molecular marker that concerned Sub1 gene. Stages of research was started from planting of BC4F1 Ciherang-Sub1 seed, testing of submergence tolerance, isolation of rice DNA, measuring of concentration and purity of rice DNA, and PCR analysis with AEX1 and RM219 markers. The test results of the submergence showed that 15 plants of BC4F1 Ciherang/Swarna-Sub1 and 21 BC4F1 Ciherang/IR64-Sub1. PCR results with markers AEX1R and AEX1F showed that the DNA band sized 231 bp, while the results of PCR with the combined markers AEX1R and RM219F can distinguish heterozygote between Ciherang rice, Swarna-Sub1 and IR64-Sub1.
Keyword: Padi BC4F1, padi IR64-Sub1

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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