Judul: Agronomic improvement characters and adaptation to drought stress on soybean [Glycine max (l) merr] through low doses of gamma rays irradiation
Abstrak: The increase in genetic variability of soybean plants improve the probability to select for desired characters, for example, adaptation to drought stress. Mutation breeding is a breeding methods that can be applied to improve genetic variability of soybean in a relatively short time. Similarly, mutation induction can also increase genetic variability of soybean by using low doses of gamma rays irradiation. The objectives of the research were : (1) to obtain information on the changes in morphological and agronomic characters due to the treatment of low doses of gamma rays irradiation on plant population; (2) to obtain information on genetic variability among irradiation doses in plant population; (3) to obtain mutant putative genotype with good morphological and agronomic characters on optimum as well as stress condition; (4) to obtain information on the character of physiological adaptation to drought and plants; and (5) to obtain to a mutant putative line which can tolerate drought and high yielding. The study result showed that in Lethal Dose 50 (LD50) value there were 457,13 Gy. Gamma ray irradiation produced four populations that showed different growth and development from the non-irradiated control (Argomulyo). Genetic variability of each trait was different in each population at M2 generation. The selection based on number of productive pods and weight of seed per plant resulted in a mean improvement of selected genotype compared to the mean of base populations in M3 generation, respectively. Putative mutant lines on M4 that was from M3 selection had a mean improvement of plant height, number of productive nodes and number of productive pods better than that of Argomulyo variety. There were different responses of drought tolerant varieties (Ceneng and Tanggamus) and drought sensitive varieties (Anjasmoro and Argomulyo) to soil water content. The escape mechanism was found as earlier maturity in Argomulyo variety. Avoidance mechanism due to the increase in root volume was found in Anjasmoro, Ceneng and Tanggamus varieties at 40 % field capacity. Tolerance mechanism was marked by the reduction of evapotranspiration in Tanggamus variety at 40 % field capacity. The research results showed that the performance of agronomic characters on drought condition were lower than that of in optimum condition in M5 population. The selection result on M5 generation indicated that the selected mutant strains had good agronomic characters and high yielding. They had good adaptability to drought and were high yielding in optimum conditions and drought conditions.
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Judul: Pendugaan Daya Simpan Galur-Galur Kedelai (Glycine max (L.) Merr.) Hasil Iradiasi Sinar Gamma dengan Metode Pengusangan Cepat
Abstrak: The objective of the research was to estimate the varians on seed storability of soybean lines selected from population of gamma ray irradiation varietes Argomulyo, with two chek varietes, namely Argomulyo as wild variety and Tanggamus as drought acid tolerant variety. The research was conducted at the Laboratory of Plant Breeding and Laboratory of Seed Science and Technology, Departement of Agronomy and Horticulture , Bogor Agriculture University from March-August 2012. The research used Nested Plot Design, with 22 soybean lines and two control varietes nested within five perioed of accelerated ageing in 0, 20, 40, 60, and 80 minutes. The result showed that there was variations for character observed due to genetic factors. Character of viability and vigour observed had heritability higher than 50% except moisture content. There was significant and positive correlations among electrical resistance and character related to seed vigour except moisture content. If the seed germination was high, electrical resistance would be high. Electrical resistance had negative correlation with electrical conductivity. It means that electrical resistance could be applied as selection character for improvement seed vigour. M100-29A-42-10, M50-45-9-12, M100-96-53-7, M100-29A-42-15, M100-96-53-6, M200-20-52-11, M200-93-49-13 had good storability.
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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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