Judul: Induksi keragaman genetik dengan sinar gamma pada jeruk siam pontianak (Citrus nobilis var. microcarpa) secara in vitro
Abstrak: Di antara berbagai jenis jeruk, jeruk siam mendominasi produksi jeruk di Indonesia. Tetapi, jenis jeruk ini masih memiliki jumlah biji yang relatif banyak, warna kulit yang kurang menarik, dan kulitnya sulit dikupas. Teknik pemuliaan konvensional pada jeruk memerlukan waktu yang cukup lama dan biaya yang besar, serta dibatasi oleh heterozigositas yang tinggi, tipe reproduktif melalui embrio nuselar dan juga juvenilitas. Pemuliaan mutasi dengan menggunakan mutagen fisik seperti sinar gamma merupakan salah satu alternatif untuk meningkatkan keragaman yang dapat mengubah satu atau lebih karakter tanpa mengubah karakteristik asalnya. Penelitian ini diharapkan dapat menghasilkan varietas unggul jeruk siam Pontianak yang memiliki karakter agronomi dan kualitas buah yang lebih baik. Percobaan ini telah dilakukan melalui beberapa tahap, mulai dari perbanyakan kalus embriogenik, iradiasi sinar gamma pada kalus, pendewasaan embrio somatik, perkecambahan embrio somatik, analisis keragaman genetik berdasarkan karakter morfologi dan analisis stomata sehingga diperoleh informasi bahwa pemberian mutagen sinar gamma dapat menyebabkan perubahan baik morfologi maupun jumlah kromosom.
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Judul: Induksi Keragaman Kalus Embriogenik Untuk Mendapatkan Mutan Putatif Jeruk Keprok Garut (Citrus reticulata L.) Melalui Iradiasi Sinar Gamma
Abstrak: Mandarin Citrus cv. Garut is one of local citrus which has some several superiority such as easy to peel, fresh and sweet flavour, yellowish green skin and containt 12-15 seeds per fruit, but can it not compete with citrus from other countries. Quality improvement have been the subject of citrus breeding programme. The objective of this research is to increase genetic variability of Mandarin Citrus cv. Garut through gamma rays irradiation on embryogenic callus. Callus was irradiated at doses of 0, 20, 30, 40, 50, 60, 70, 80, 90 and 100 Gy and regenerated through somatic embryogenesis. The result of radiosensitivity dose for Growth Reduction (GR50) analyzed by Curve Expert 1.4 software was 75.31 Gy. Observation on the growth of callus showed variation on morphology and weight of callus. At doses 0–50 Gy callus growth was not inhibited, but at doses 60–100 Gy callus growth was inhibited. Gamma irradiation also affected the formations of somatic embryos. After six weeks on maturation medium produced the highest of embryo somatic at dose of 20 and 100 Gy and on germination medium produced planlet highest at dose of 20 and 40 Gy. Based on morphological characters selected 10 regenerants with variability of 0–58% and genetic variability with ISSR markers by 0–26%. The number of mutan putative produced were M30/2, M50/1, M80/3 and M100/1 comformed by ISSR. After four week grafting between putative mutan shoots as scion and Japansche Citroen as rootstock it was obtainted the growth percentage 37.5-50% on Ex Vitro Grafting and 75% on In Vitro Grafting.
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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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