Judul: Keragaan dan Keragaman Mutan Tanaman Ubi Kayu (Manihot esculenta Crantz.) Hasil Iradiasi Sinar Gamma Serta Pendugaan Heritabilitas
Abstrak: Cassava is a potential crop for food, industry (food and feed), and bioenergy if developed suit with their characteristics. This research intended to identify the second generation (M1V2) cassava mutants from gamma ray irradiation. The irradiated cassava varieties are Ratim, UJ-5, and Malang-4. The result show that mutant variability appears on mutants plant performance (plant height, plant branching, tubers weight, number of tubers and economic tubers, cortex thickness and tuber qualitative characters). Variability in each genotype also appears on the tuber performance in this generation. Broad sense heritability estimation on number of tubers, number of economic tubers and cortex thickness were classified as high score and can used as third generation mutant selection criteria. The shelf life of cassava tubers depends on postharvest physiology deterioration (PPD) and marked by changes in water content and tuber discoloration, PPD occurs in almost all mutant genotype samples stored up to 21 days.
Keyword: Bogor Agricultural University (IPB), storage root, mutant, characterization, M1V2 generation

Judul: Karakterisasi Morfologi dan Pertumbuhan Beberapa Genotipe Ubi Kayu (Manihot esculenta Crantz) Hasil Induksi Mutasi Menggunakan Iradiasi Sinar Gamma
Abstrak: Penelitian ini bertujuan untuk mempelajari pertumbuhan dan keragaman beberapa genotipe ubi kayu yang telah diinduksi iradiasi sinar gamma. Setek batang ubi kayu diiradiasi di Laboratorium Pusat Aplikasi Teknologi Isotop dan Iradiasi (PATIR), Badan Tenaga Nuklir Nasional (BATAN) kemudian ditanam di Kebun Percobaan Cikabayan IPB pada bulan Mei 2012 sampai April 2013. Penelitian dirancang menggunakan rancangan kelompok lengkap teracak (RKLT) dengan dua faktor, faktor pertama yaitu dosis iradiasi sinar gamma yang terdiri atas lima taraf yaitu 0, 15, 30, 45, dan 60 gray, faktor kedua adalah perbedaan genotipe yang terdiri dari Ratim, Jame-jame, UJ5, Malang 4, dan Adira 4. Hasil penelitian menunjukan iradiasi mengakibatkan tanaman mati sebanyak 146 tanaman saat berumur 0-2 bulan setelah tanam (BST). Perlakuan iradiasi mengakibatkan berkurangnya jumlah stomata dan jumlah umbi terhadap beberapa genotype. Perlakuan iradiasi 15 gray menghasilkan tinggi tanaman dan umbi yang lebih besar dibandingkan kontrol dan dosis 30 gray. Hasil karakterisasi menunjukan bahwa perlakuan iradiasi mengakibatkan berubahnya karakter morfologi beberapa genotipe ubi kayu.
Keyword: cassava, characterization, genotypes, morphology, mutations

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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