Judul: Studi Pembungaan Sorgum (Sorghum bicolor (L.) Moench) untuk Seleksi Galur Tetua Persilangan
Abstrak: Selection of parental stock for variety improvement needs understanding of flowering characteristic. The experiment was aimed at obtaining informations on flowering biology of sorghum and reproductive potential for selecting potential lines as parents. The experiment was conducted in IPB University Farm, Leuwikopo, Bogor with 10 sorghum lines. Evaluation of quantitative and qualitative characters observed was based on indicators described by IBPGR. Lines that were used were N/UP 82-3, N/UP 118-7, N/UP 89-3, P/I 150-20 A, P/I 10-90 A, P/I 150-21 A, P/I 5-193 C, UPCA, Numbu and Kawali. The ten sorghum lines showed variability in agronomic characters. The line suitable for parental line to improve plant height is P/I 150-20 A, they are good candidates for parental line to improve spike characters except N/UP 89-3 and N/UP 118-7. Numbu and N/UP 118-7 are the best line to be used as parental line to improve yield potential. The sorghum lines showed variability in the stigma colour, spike exsertion and type of panicle, but all have similar panicle density at maturity. The lines are good candidate as parental lines to improve panicle exsertion except N/UP 89-3 and N/UP 118-7. The sorghum lines showed variability in time to flowering and the best pollen viability was obtained at anthesis from different parts of the panicle (distal, middle, proximal).
Keyword: viability, pollen, anthesis

Judul: Keragaan Karakter Agronomi dan Keberhasilan Persilangan Galur-galur Sorgum (Sorghum bicolor (L.) Moench)
Abstrak: The objectives of this experiment were to determine the performance character of the parental lines and crossing ability of sorghum (Sorghum bicolor (L.) Moench) lines. This research was carried out in the Leuwikopo Experimental Farm, Bogor Agricultural University, Dramaga, Bogor and started from February 2013 to July 2013. This experiment was arranged by two sebdivission. The first experiment was arranged in a randomized complete block design with one factor and three replications, and the second was arranged in line x tester crossing methode. Performance of agronomic traits of the parental lines showed significant differences with Numbu and Kawali varieties in all variables, except the germination variable. Performance of yield comoponent in sorghum lines showed significant differences with Numbu and Kawali varieties, especially on the character length of panicle and thousand grain weight. The results showed a positive correlation between agronomic characters and yield component. The results showed that the cross compatibility introduced lines was higher than IPB breeding lines and mutant lines of sorghum. The successful at the each lines did not indicate correlation of the climate components
Keyword: yield component, hybridization, agronomy character

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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