Judul: Respons Ketahanan Sumberdaya Genetik Lokal Cabai (Capsicum spp.) terhadap Infeksi Virus Daun Keriting Kuning dan Identifikasi Faktor Inisiasi Translasi 4E (eIF4E)
Abstrak: Chili pepper (Casicum spp.) is one of the most important horticultural crops in Indonesia. The limiting factors to improve the total production and quality in chili ware caused by pepper yellow leaf curl virus, was transmitted by the insect called Bemisia tabaci Genn. Economically, yield loss due to viral infection are very high due to persistent viral attacks. The use of resistant genotypes is one of the most effective methods to control the disease. To obtain resistant varieties, a series of plant breeding activities are required, starting from finding sources of germplasm, selecting parental lines, crossing, developing genotypes, testing genotypes and releasing varieties. Screening for resistance to viral infection was carried out on 14 genotypes of chili collections from the Center for Tropical Horticultural Studies (PKHT). The research activities included testing the resistance response of 14 genotypes of chili plants against pepper yellow leaf curl virus, and identification of translation initiation factor 4E as a candidate gene responsible for recessive resistance. The first activity was aimed to obtain resistant genotype candidates from 14 local genotypes chili pepper collection from PKHT. The artificial inoculation was carried out on 14 genotypes of chili peppers through B. tabaci as a vector which previously acquired on plants infected by yellow leaf curl virus. The study was conducted in a greenhouse using a one-factor randomized complete block design, with genotype as a factor and replicated 3 times. Observation parameters include disease incubation period, scoring the disease symptom, disease incidence and severity values, several quantitative plant characters, heritability in broad sense values and correlations between quantitative characters. The results grouped plants into four categories, resistant, moderately resistant, moderately susceptible and susceptible. Genotypes with susceptible categories, were PKHT-4 and CR-MH, moderately susceptible were PKHT-2, PKHT-3, PKHT-5, CR-SH, moderately resistant were PKHT-1, PKHT-6, PKHT -7, CR-SA, CB-BA, CB-BJ, and CB-CA, and the only resistant category were found in genotype CB-EL. The broad sense heritability values for disease resistance were moderate-high categories, and the correlation quite high. This showed that selection for the disease resistance against virus can be done at the early stage of planting, and the genotypes which show resistant character can be developed as a parental candidates. To see the presence of viral infection in plants, molecular analysis was carried out using degenerate primers Begomovirus SPG1/SPG2. The amplification results produce a band size around 900 bp. This indicates that the plant is positively infected with the disease-causing virus. The second activity was isolation and identification of translation initiation factor 4E (eIF4E) to obtain candidate genes responsible for recessive resistance against Begomovirus infection. The results of amplification with primers AY122F/AY122R were 500 bp, in accordance with the expected size of the primer, which was 529 bp. It showed that the fragment of the DNA was detected and amplified, except for the genotipe number 13 (no band produced), which was CB-EL. It is suspected that the CB-EL genotype has resistance that is controlled by the recessive allele. Lost of function of eIF4E inhibited viral proliferation and the CB-EL genotype was not detected during amplification using S-gene primers. Furthermore, sequencing was
Keyword: B. tabaci, heritability, recessive resistant, selection

Judul: Karakterisasi beberapa genotipe cabai (Capsicum spp.) dan mekanisme ketahanannya terhadap begomovirus penyebab penyakit daun keriting kuning
Abstrak: The plant breeding program to develop resistant plants of Begomovirus is needed to characterize of pepper germplasm. The activities followed by study on resistance mechanism based on information of structural and biochemical resistance against Begomovirus and their vector Bemisia tabaci. Pepper yellow leaf curl virus (PYLCV) belongs to the genus of Begomovirus, the family members of Geminiviridae. The virus has been reported as the causal agent of yellow leaf curl disease in pepper and transmitted by an insect vector, B. tabaci Genn. Evaluation of genotypes characters showed that the morphological characters of leaves, stems, flowers, and fruits can be distinguished among the genotypes of pepper. There are significant differences among pepper genotypes for the following variables: height of dicotomous, plant height, canopy width, stem diameter, leaves length and width, and flowering times. Dendrogram analysis based on qualitative characters involving 29 genotypes classifies the genotypes into 4 different groups. Most of the genotypes belong to group I, genotypes IPB C15 and IPB C63 are in group II, IPB C12 genotype in group III, whereas IPB C20 and IPB C21 are in group IV. All genotypes are included in C. annuum, except IPB C63 genotype which belongs to C. frutescens. Capsicum species differs in the form of leaves, number of flowers at per node, the position of flowers, fruit color intermediate, and plants canopy. Resistance response of the genotypes was identified based on the measurement of disease intensity. IPB C12 genotype is resistant; IPB C10 and IPB C14 genotypes are moderately resistant; IPB C15, IPB C26, and 35C2 genotypes are susceptible. PYLCV detection using PCR technique has successfully amplified 780 bp-sized Begomovirus-specific DNA fragments. Dot blot hybridization is capable to detect PYLCV in resistant and moderately resistant genotypes to a dilution level of 1: 10, whereas susceptible genotypes can reach up to 1: 100 dilution level. Susceptible genotype tended to have a Begomovirus concentrations higher than genotypes resistant or moderate resistant. Genotypes resistance to Begomovirus is associated with structure of plants i.e. density of trichome and arrangement of palisade cells. An increased accumulation of salicylic acid and peroxidase enzyme activity are detected in Begomovirus-inoculated plants, 120 hours after inoculation. Based on the correlation among characters in pepper genotypes, it can be concluded that there is a correlation between the mechanisms of structural and biochemical resistance of plants following Begomovirus infection. Longer palisade cells will lead to thicker leaf and more accumulation of salicylic acid. Trichome density and palisade cells position are the structural barrier in the mechanism of pepper resistance to B. tabaci. Resistance mechanism to Begomovirus is the result of the width of palisade cells, increased accumulation of salicylic acid, and increased activity of peroxidase enzymes. There is a correlation between the structural and biochemical mechanisms to Begomovirus, with a positive correlation between the lengths of palisade cells and salicylic acid accumulation.
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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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