Judul: Genetik ketahanan cabai terhadap begomovirus penyebab penyakit daun keriting kuning dan arah pemuliaannya, Genetics of resistance on chili pepper to yellow leaf curl begomovirus and strategy breeding
Abstrak: Begomovirus has been reported as the major pathogen for various important crops, including chilli pepper. Disease severity and yield loss caused by Begomovirus infection are affected by several factors, among others are plant varieties, viral strains and time of infection. The use of resistance varieties is considered as the most effective way to control the disease. Research activities were conducted to study the genetics of resistance of chilli pepper varieties to Pepper yellow leaf curl Begomovirus, in order to develop resistance chilli pepper varieties. Preliminary experiment was conducted to determine the transmission method using insect vector, Bemisia tabaci followed by determination of plant stage for inoculation of Begomovirus. Individual inoculation using 10 insects per plant with 24 h acquisition period and 48 h inoculation period on cotyledon stage was considered as the most effective and efficient way for Begomovirus transmission. Type of symptoms develop from Begomovirus infection can be differentiated into 5 groups, i.e (1) yellowing (2) yellowing and leaf curling (3) yellowing, leaf cupping with leaf curling, upward or downward, (4) yellowing, leaf cupping with leaf curling, upward and downward (5) yellowing, leaf curling, stunting. Twenty seven genotypes of chilli pepper were evaluated for their resistance based on score/type at symptoms and disease intensity. Disease intensity was ranged from 2.40% to 100% and they were group grouped into resistance (1 genotipe), moderate resistance (4 genotipes), moderate susceptible (4 genotipes), susceptible (8 genotipes) and highly susceptible (10 genotipes). Further analysis showed that resistance genotype (IPBC12) has more trichome than susceptible genotype (35C2) does salicylic acid contain was not significantly different between two genotypes, although Begomovirus infection could increase salicylic acid contain in resistance genotype. Genetic studies for resistance of chilli pepper to Yellow leaf curl Begomovirus was conducted using two methods, i.e. (1) analysis ofbasic population using six-population analysis and (2) analysis of random mating using diallel analysis. The result indicated that pepper resistance to Begomovirus was controlled by polygenes and there was extrachromosomal effect. The degree of dominance were over dominant. Gene action for resistance were additive, dominant and additive x additive interaction. However one population (IPBClO x IPBC14) showed additive gene action, dominant, additive x additive and dominant x dominant interaction. Estimation of broad-sense heritability were high but narrow-sense heritability were low to high. IPBC12 dan IPBC10 have the best combining ability for resistance to Begomovirus whereas IPBC14 have the highest yield. There are four crossing, i.e. IPBC10xIPBC12, IPBC12xIPBC14, IPBC14xIPBC18, dan IPBC18xIPBC26, that good combining ability and heterosis for resistance to Begomovirus and yield. Resistance verieties to Begomovirus could be established through hybrid cultivars to benefit the effect of dominance gene action. However, it could also be developed through open pollination using bulk or pedigree method.
Keyword: resistance, susceptible, combining ability, chilli pepper, Begomovirus

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: 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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