Judul: Study on the resistance of hot pepper (Capsicum annuum L) to anthracnose disease
Abstrak: The research was conducted in the greenhouse of The Department of Agronomy and Laboraty of The Department of Plant Pest and Disease, Faculty of Agriculture, Bogor Agricultural University from April 2000 to March 2001. The objective of this research was to evaluate the best method and time of inoculation, and the resistance of four hot pepper genotypes to anthracnose on pre and post harvested fruits. Resistance evaluation on pre-harvested fruits was done in the greenhouse with "spray" inoculation method of lo6 sporedml Colletotrzchum gloeosporzoides suspension at flowering stage and fruit-set stage. Resistance study on post-harvested fruits was done in the laboratory with "paste" method of inoculation on mature green and mature red stage fruits. Both experiments were set in a factorial and completely randomized design with four replications and five plants per experimental unit. The genotypes evaluated were UPM, Titsuper, Yogya, and Jatilaba. Observations were done on disease severity, disease incidence and percentage of fruit damage.
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Judul: Genetic parameters estimation of pepper (Capsicum annuum L.) resistance to anthracnose (Colletotrichum acutatum) using diallel analysis
Abstrak: Anthracnose (Colletotrichum acutatum) is considered of the major disease that may cause significant yield losses in pepper. Resistance variety is important for controlling disease infection since other methods were not effective. The aim of this research is to identify pepper genotype resistance and estimating genetic parameters of pepper resistance to anthracnose. This experiment were done in three steps: (1) screening of pepper resistance to anthracnose, (2) estimating genetic parameters of pepper resistance to anthracnose using diallel analysis and (3) determining the selection character using path analysis. The first experiment was conducted using 21 genotypes and C. acutatum isolate BKT 04. Mature green fruit were inoculated using microinjection method. The result showed that based on disease incidence, there was no genotype which resistance to anthracnose. However, there were three genotypes (IPB C15 x IPB C10, IPB C15 and IPB C8) which resistance based on lesion diameter. Set population from half diallel crosses which involve 6 parents and 15 crosses with C. acutatum isolate BKT 04 were used in the second experiment. Disease resistance percentage and lesion diameter were used for estimating genetic parameters and combining ability. Disease incidence and lesion diameter were used for estimating heterosis. The results show that there is no non alellic interaction, gene effects for resistance to anthracnose were additive and dominance, dominance effect larger than additive effect, the degree of dominance was overdominance, genes distribution in the parents was assymetrical, anthracnose resistance was controlled by one gene group, broad-sense heritability was high and narrow-sense heritability was low. General combining ability of IPB C15 was high for disease resistance percentage and lesion diameter, specific combining ability of IPB C15 x IPB C9 was high for disease resistance percentage and specific combining ability of IPB C15 x IPB C10 and IPB C4 x IPB C2 were high for lesion diameter. Negative heterosis was expected in disease resistance traits, IPB C15 x IPB C9 had negative heterosis for disease incidence and IPB C10 x IPB C9 had negative heterosis for lesion diameter. The thickness of fruit flesh is recomended for selection criteria for developing anthracnose resistant pepper varieties.
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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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