Judul: Induction of genetic variability through gamma rays irradiation on embryogenic callus derived protoplast of tangerine cv. siam
Abstrak: Tangerine cv. Siam has sweet flavor, easily peeled skin, soft and juicy flesh. However, it has relatively many seeds (15-20 seeds per fruit), so it can not be competed with citrus from other countries. Fruit quality improvement of citrus has been the subject of citrus breeding program. The first step of breeding program is to increase variability, in order to efficient the selection process. Callus derived protoplast which sub cultured several years has a level of variability. The objective of this research was to increase variation of Tangerine cv. Siam through gamma irradiation on callus derived protoplast. Callus was exposed to gamma irradiation at 0, 10, 20, 30, 40, 50, 60, 70, 80, 90 and 100 Gray. Observation on the growth of callus four weeks after irradiation showed variation on morphology and weight of callus. At low doses (10-50 Gray) callus growth were not inhibited, but at high doses (60-100 Gray) callus growth were inhibited. The result of radio sensitivity dose analyzed by Curve Expert 1.4 software was 53.25 Gray. Callus regeneration ability (somatic embryo maturation and germination) were very diverse between irradiated and non-irradiated callus. Gamma irradiation affects the formation of somatic embryos. After four weeks on MW (Morel-Wetmore) medium containing 0.5 mg/l ABA, 50 Gray callus produced more somatic embryos than other doses. After four weeks on MW medium containing 0.5 mg/l GA3, only 75.9% somatic embryos from 50 Gray callus could germinate, less than other doses. All somatic embryos from non-irradiated callus could germinate. The germination of somatic embryos produced 72 regenerated plantlets. Dendogram based on morphological observations of 0 Gray regenerated plantlets showed 40% variability, while of 50 Gray were 47% and that of 60 Gray were 46%. Ten regenerated plantlets were chosen based on its variability and growth (P-2, P-8, 50-4, 50-6, 50-15, 50-24, 60-8, 60-10, 60-11 and 60-23). Dendogram based on morphological observation between 10 regenerated plantlets showed 30% variation. Molecular analysis of the 10 regenerated plantlets using three ISSR primers (ISSR-1, ISSR-2 and ISSR-4) produced 17 bands with nine polymorphic bands (52.94%). Dendogram based on molecular analysis between 10 regenerated plantlets and wild type shoots showed 22% genetic variation. In vitro and ex vitro grafting between regenerated plantlets and JC rootstock could accelerate optimal growth of plantlets. Application of ex vitro grafting was more efficient than in vitro grafting. Ex vitro grafting did not need acclimatization stage, where as in vitro grafting still need acclimatization stage before transfer to soil.
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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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