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: Propagasi mikro dan Sambung Mikro Jeruk Keprok Garut (Citrus reticulata) Hasil Mutagenesis In Vitro dengan Batang Bawah Japansche Citroen
Abstrak: This study aimed to get proper concentration of kinetin for multiplication of Mandarin var. Garut as derived from in vitro mutation, to determine period of immersion of Japansche citroen seed in GA3 10 mg/l solution and to get proper concentration of sucrose concentration in agar for grafted plant. This research is consist of three steps. For the first step, shoot as derived from in vitro mutation multiplicated with 2 books cutting and planted in standard medium with kinetin 1 mg/L, 3 mg/L, 5 mg/L added. For the second step, JC seed immersed in 10 mg/L of GA3 for 1, 2, and 3 hours and planted in standard medium. For the last step, explant from the first and second step was grafted and planted in standard medium with sucrose 30 g/L, 50 g/L, and 70 g/L. The optimal concentration of kinetin for scion growth is 1 mg/l and for multiplication is 5 mg/l. The best period for rootstock immersion in GA3 solution is 3 hours. The best percentage of success micrografting occured in 70 g/l sucrose medium.
Keyword: Bogor Agricultural University (IPB), sucrose, multiplication, kinetin, gibberellin

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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