Judul: Aplikasi marka molekuler untuk seleksi padi galur bc1f1 code x qtsn4 dengan produktivitas tinggi
Abstrak: Salah satu varietas padi inbrida unggul tahan hama dan penyakit hawar daun bakteri adalah code, namun potensi hasil padi code masih rendah. Hal tersebut mendorong dilakukannya perbaikan genetik kultivar padi code untuk meningkatkan potensi hasil padi code. Penelitian ini bertujuan menyeleksi galur tanaman bc1f1 turunan code x ir64-nils-qtsn4[yp9] yang memiliki gen xa7 dan qtsn4 menggunakan marka molekuler serta analisis karakter agronomi tanaman padi tersebut. Padi bc1f1 code x qtsn4 yang digunakan merupakan hasil persilangan balik antara code dan ir64-nils-qtsn4[yp9]. Sebanyak 250 individu bc1f1 diseleksi secara molekuler menggunakan marka ssr rm20582 (gen xa7), rm6909, dan rm17483 (qtl qtsn4). Berdasarkan analisis molekuler telah dipilih 178 individu bc1f1 yang memiliki pola genotipe heterozigot gen xa7 dan homozigot qtl qtsn4. Delapan tanaman bc1f1 memiliki jumlah bulir isi lebih banyak dari code dengan peningkatan tertinggi sebesar 31.7%.
Keyword: code, ir64-nils-qtsn4[yp9], padi, ssr

Judul: Aplikasi Primer Mikrosatelit pada Proses Seleksi Padi Varietas Code untuk Sifat Umur Berbunga
Abstrak: Code is a variety of rice resistant to bacterial leaf blight disease, but heading date of Code variety is long. It encouraged genetic improvement of Code variety to shorten the heading date. The improvement of Code by inserting qDTH8 that controls heading day character is expected to shorten harvest time and to increase yield of harvest per year. This study was aimed to select BC1F1 CodeqDTH8 lines using microsatellite primer or SSR (Simple Sequence Repeat) of PCR molecular analysis method and to analyze agronomic characters of BC1F1. As many as 250 lines of BC1F1, derived from Code and IR64-NILs-qDTH8 [YP1] were screened using RM5556 (qDTH8), RM6838 (qDTH8), and RM20582 (Xa7) primers. Based on the molecular analysis, there were 136 cultivars from 250 cultivars that had same genotype pattern of heterozygote allele for Xa7 and homozygote allele for qDTH8. The heading date of BC1F1 has been shorten by 14 days based on observation of agronomic characters in 136 BC1F1 cultivars.
Keyword: Bogor Agricultural University (IPB), Rice, SSR, qDTH8, IR64-NILs-qDTH8 [YP1], Code

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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