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: Performance of Morpholgical, Agronomic and  Yield Potential of F7 Sorghum Breeding Lines IPB Selected through Pedigree and  Bulk Method
Abstrak: Galur hasil pemuliaan tanaman perlu dikarakterisasi secara lengkap mencakup karakter morfologi, agronomi, dan komponen hasil. Penelitian bertujuan untuk mempelajari keragaan morfologi, agronomi, potensi hasil; menyeleksi galur unggul; serta mengelompokkan galur-galur F7 sorgum berdasarkan kemiripan karakter. Penelitian ini dilaksanakan mulai bulan Februari hingga Juli 2021 di Kebun Percobaan Leuwikopo, Laboratorium Mikroteknik, dan Laboratorium Pemuliaan Tanaman, Departemen Agronomi dan Hortikultura, IPB. Rancangan percobaan menggunakan rancangan kelompok lengkap teracak satu faktor yaitu genotipe. Genotipe sorgum yang digunakan berjumlah 17 galur F7 sorgum IPB serta 5 varietas pembanding yaitu Numbu, Kawali, Soraya IPB 2, PI-10-90-A dan PI 150-20-A. Kemiripan galur berdasarkan karakter morfologi, agronomi, potensi hasil dianalisis menggunakan software PBSTAT-CL. Hasil penelitian menunjukan galur-galur F7 memiliki karakter yang beragam, kecuali pada karakter lebar daun, jumlah daun hijau saat maturity, diameter malai, kandungan gula (brix) batang fase generatif, kerapatan malai saat matang dan kandungan antosianin pada daun. Galur A-1-23-1-1 memiliki jumlah daun hijau saat anthesis nyata lebih banyak dibandingkan seluruh pembanding serta daun hijau saat maturity lebih banyak terhadap seluruh pembanding. Galur A-18-3-4-7, A-18-12-7-5, B-14-25-5-6 merupakan galur dengan kandungan gula (brix) saat panen nyata lebih besar terhadap pembanding Kawali. Galur A-21-14-2-1, B-14-25-5-6, C-375-17-5-9 memiliki potensi hasil nyata lebih besar terhadap pembanding PI-150-20-A., Sorghum breeding lines need to be characterized include morphological, agronomic, yield potential. This study aim to learn about morphological, agronomic and yield potential; lines selection superior; grouping of sorghum genotypes based on character resemblance. Experiment was conducted from Februari to July 2021 at Leuwikopo experiment field of IPB University, Microtechnical Laboratory, and Plant Breeding Laboratory Department of Agronomy and Horticulture, IPB University. Experimental design used was a randomized complete block design with genotype as the treatment factor. The plant materials used were 17 F7 lines and 5 varieties as control is; Numbu, Kawali, Soraya IPB 2, PI-10-90-A, PI-150-20A. The similarity of the lines was analyzed using PBSTAT-CL software. Genotype F7 lines had varios on characters; except for character of leaf width, number of green leaves at maturity, panicle diameter, sugar iii content (brix) of generative phase stems, panicle density when ripe and anthocyanin content in leaves. A-1-23-1-1 line had more green leaves at anthesis and maturity than all comparisons. A-18-3-4-7, A-18-12-7-5, B-14-25-5-6 were lines with significantly higher sugar content (brix) at harvest than the Kawali comparison. The lines A-21-14-2-1, B-14-25-5-6, C-375-17-5-9 had significantly higher yield potential than the PI-150-20-A
Keyword: bioethanol, brix, cluster analysis, qualitative, quantitatif

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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