Judul: Phenotipic Variation of F7 Rice Lines Derived from a Cross between IR64 X Hawara Bunar Under Aluminum Stress.
Abstrak: Aluminum(Al) toxicity is onethe most important limiting factors for upland rice growth and production in acid soils. This study was aimedtoanalyze the diversity of phenotypes and to select an F7 rice Recombinant InbreedLines(RIL) population derived froma crossbetweenricevarietasIR64 and Hawara Bunar for Al resistance. The experiment used 300 rice lines fromthe F7 RILpopulationand 3 control varieties which were IR64 (Al-sensitive), Hawara Bunar (Al-tolerance), and Danau Gaung (Al-tolerance). The experiment was designed using Randomized Complete Block with single factor and 3 replication.The experiment carried out in 3 places; the laboratory, the greenhouse and the field. The results showed that based on Relative Root Legth (RRL) as a selection character, the 300 rice linescould be grouped into 130(43%)high Altolerant lines, 68(22.6%) moderate Al-tolerant and 102(34%)Al-sensitivelines. The green house experiment using 50 selected rice lines that were grown in Yellow Red Podzolic acid soil could select 32 lines that were Al-tolerant with good agronomic characteristics. The field experiment using 32 selected rice lines that were grown in Yellow Red Podzolic acid soil in Taman Bogo, Lampungcould select 4 lines (161, 322, 531, 699) that were tolerant to Al stress and acid soilwith good agronomic characteristics.
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Judul: Molecular Marker Application on Selection of A Rice Backcross Population derived from a Cross between IR64/Hawara Bunar to Obtain Aluminum-Tolerant Rice Lines
Abstrak: Since 1971 the increase of food demand in Indonesia, especially rice is much greater (181.6%) than the increase of population (108%), therefore an effort to increase rice production is unavoidable. Currently, the ability of agricultural land to provide area for rice cultivation tends to decline from year to year due to massive conversion of productive lands into industrial and residential uses. The situation leads to expand rice cultivation into the utilization of marginal lands, such as acid soils for rice cultivation. However, rice cultivation in acid soils will face many constraints, which mainly due to the aluminum (Al) toxicity. The use of Al-tolerant rice varieties with high productivity will be an alternative solution to overcome the Al toxicity problem in acid soils. There is an Indonesian local rice genotype named Hawara Bunar that tolerant to Al stress and can be used as a Al-tolerant donor parent in rice breeding program. However, the potential productivity of the genotype is not as high as rice cv IR64. The use of a backcross population derived from a cross between both genotypes with cv IR64 as a recurrent parent is an approach to develop Altolerant rice cultivar with high productivity. It has been identified that a Quantitative Trait Loci (QTL) for Al-tolerance trait is located on the short arm of rice chromosome 3 flanked by markers RM489 and RM517 (Miftahudin et al. 2008; Akhmad 2009). The objectives of the study were to (1) increase molecular markers density in the area of QTL for Al-tolerance trait on rice chromosome 3 flanked by two SSR markers RM489 and RM517, (2) re-identify QTLs for Al tolerance trait in the previous Al-tolerance QTL area on rice chromosome 3, (3) and carry out marker assisted backcross selection (MABS) ob a rice backcross population derived from a cross between IR64/Hawara Bunar to obtain Al-tolerant rice lines with superior agronomic traits. The research was conducted from September 2009 to May 2012 at the Laboratory of Plant Physiology and Molecular Biology, Department of Biology, Bogor Agricultural University and at the Research Institute for Agricultural Biotechnology and Genetic Resources (Biogen) Bogor. An F2 population derived from a cross between rice cv IR64 and Hawara Bunar were used to increase marker density and re-identify Al-tolerance QTL, while BC2F1 plants and BC2F2 populations that have been developed from the previous and this studies, respectively, were selected through MABS combined with physiological and agronomic characters based selection. An amount of 17 SSR markers were screened for polymorphism between the two parents to obtain markers that being used to increase marker density. Five markers, which were RM2790, RM545, RM14535, RM14543, and RM14552, were polymorphic and could be mapped in between markers RM489 and RM517 with the average distance of 3 cM between adjacent markers. Al-tolerance QTL were identified in the previous QTL location between markers RM2790 and RM14552 (LOD 3.4) based on the Main Root Elongation characters. Foreground and background selections were successfully carried out on BC2F1, BC2F2 and BC2F3 populations using five foreground and 50 background SSR markers. The MABS obtained two BC2F3 rice lines (number 175-63-34 and
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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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