Judul: Response  of  soybean  genotypes  (glycine  max  l.  merrill)  from  various  countries  to  environmental  of  grow  conditions at wet tropical agroecosystem
Abstrak: Penelitian ini bertujuan untuk mempelajari respon pertumbuhan dan produksi 130 genotipe kedelai dari berbagai negara terhadap kondisi lingkungan tumbuh agroekosistem tropika basah. Percobaan ini disusun dengan rancangan augmented dalam rancangan acak lengkap (RAL). Benih kedelai yang digunakan sebagai pembanding (kontrol) adalah kedelai varietas Tanggamus, Anjasmoro, Argo Mulyo, Wilis dan Tachinagaha (varietas Jepang) yang terdiri dari 5 ulangan sehingga terdapat 150 satuan percobaan. Hasil penelitian menunjukkan bahwa genotipe GmWMC192 yang berasal dari Nepal berdaya hasil tinggi dan beradaptasi baik pada lahan kebun percobaan IPB Sawah Baru. Hal ini dilihat dari persentase tanaman yang tumbuh di lapangan, tinggi tanaman, jumlah buku, jumlah polong per tanaman, dan persentase biji penuh yang tinggi. Selain itu, genotipe GmWMC019 dan GmWMC042*2 yang berasal dari Korea Utara dan Republik Rakyat Cina berumur sangat genjah (66 hari) serta beradaptasi baik pada lahan kebun percobaan IPB Sawah baru. GmWMC019 dan GmWMC042*2 merupakan genotipe yang peka terhadap suhu tinggi, This research aims to study the response of growth and production of 130 soybean genotypes from various countries to the condition at wet tropical agroecosystem. The experimental design used was augmented design in randomized complete design (RCB). Soybean seed that was used as check varieties are Tanggamus, Anjasmoro, Argo Mulyo, Wilis and Tachinagaha (Japan soybean variety) consist of 5 replicates so there are 150 units of the experiment. The results indicated that the genotype GmWMC192 from Nepal has high result and adaptable at the field of Bogor Agricultural University. It is seen from the percentage of the survived plants, plant height, the number of node, number of pods per plant, and higher percentage of full seeds. In addition, genotypes GmWMC042*2 and GmWMC019 from North Korea and China have very fast growth (66 days) and also adaptable at the field of Bogor Agricultural University. Both of the genotypes may be useful as a source in soybean breeding
Keyword: biji penuh, jumlah buku, rancangan augmented, tropika basah

Judul: Respon pertumbuhan tanaman kedelai [Glycine max (L.) Merr.] pada kondisi kekeringan dan cekaman aluminium
Abstrak: The government has launched the soybean self sufficiency by 2014 in an effort to enough needs domestic of soybean . This will be achieved by increased productivity , expansion of cropping intensity and extension of planting area. A extension of the planting area is to utilize marginal lands. The mostly marginal lands in Indonesia is dryland acid soil and has the potential to be developed as an extension of planting area. The cultivation in dryland acid soil had several constraints, such as drought and high solubility of Al3+. The soybean response to water deficit varies depending on the genotypes, and the duration of the stress and growth phase. High solubility of Al3+ in the soil inhibits root growth. The experiment was carried out to study the growth response and the mechanisms of adaptation the soybean genotypes to drought and aluminum stress, which consists of the two stages experiments. The first stage was carried out to study the effect of genotype, drought and aluminium stress on the vegetative and generative growth and the plant roots of soybean. The second stage was carried out to study the effect of genotype, drought and aluminium stress on component crops of soybean. This experiments was conducted in Januari to November 2011, in the greenhouse Cikabayan, University Farm, IPB Darmaga Bogor. This study used a randomized complete block design, with three factors: 1) soybean genotypes (SP 30-4, Anjasmoro, PG 57-1 and Tanggamus), 2) watering interval (2 days, 6 days and 10 days, 3) the level of Al neutralization (0% neutralization and 100% neutralization). The results show that the adaptation mechanism avoidance of soybean geno types was only seen in PG57-1 on root length variables when gripped by drought. This mechanism can be seen from its root elongation when gripped by drought. The higher of value of the observed variables would be the higher the number of pods produced. It also happens to variable root dry weight and dry weight of root nodules. In general, yield components of soybean more influenced by drought stress. However, flowering only variable affected by Al stress on different genotypes.
Keyword: aluminium stress, drought stress, the mechanisms of adaptation

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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