Judul: Karakterisasi dan Evaluasi Keragaman Genotipe Semangka Lokal
Abstrak: Characterization is one of the first phases of plant breeding activities of watermelon. The process will trigger the appeareance of genetical diversity of the plants. The information regarding the genetical diversity of the observed characteristics is worthwhile the next phases of the breeding process. The experiment intends to achieve information of genetical diversity and directs for future research of the relations between the genetic relationship between watermelon genotype based on the level dissimilarities. The experiments has been implemented at the University Farm Leuwikopo, Bogor Agricultural University from October 2014 until January 2015. The experiment was arranged in a randomized complete block design with 8 genotypes of the exploration result and 1 genotipe for comparison. The diverse result of the analysis concludes that the test genotypes have certain effects to the observed characteristics. The characteristics of the weight of the fruit, length of the fruit, thickness of the pericarp, the total soluble solid of flesh, the day of flowering, and the harvest day have a high broad sense heritability predictive value. The character of the length of pedicel and the perimeter of fruit have medium broad sense heritability predictive value. Based on the hedonic test, genotype Bengkulu 3 was the only preferred by the panelist due to its color, scents, texture, and the taste of the fruit characteristics. The result of cluster analysis conclude that genotypes originated from same origin generally will be grouped to the group of same genetic relationship.
Keyword: Bogor Agricultural University, cluster, exploration, genetic relationship, hedonic, heritability

Judul: Keragaman genetik beberapa varietas semangka (Citrullus lanatus [Thunb.] Matsum & Nakai var. lanatus) berdasarkan karakter agronomi dan ketahanan terhadap penyakit layu fusarium (Fusarium oxysporum f.sp. niveum Snyder & Hansen)
Abstrak: Breeding for disease resistance and high yield as well as fruit quality e.g. attractive rind and flesh colors are of watermelon improvement strategies to better meet market demands. Thus, evaluation and analysis of genetic variation toward agronomical characters on commonly cultivated watermelon varieties would be one of Indonesia initial watermelon breeding programs. This work should be collaborated with evaluation in cultivar disease resistance e.g. fusarium wilt (Fusarium oxysporum f.sp. niveum), of which its control so far still depends on resistant cultivar. The study consisted of two experiments : (1) Evaluation toward agronomical characters on watermelon varieties (Citrullus lanatus [Thunb.] Matsum & Nakai var. lanatus) and (2) Evaluation toward resistance against three isolates of Fon (Fusarium oxysporum f.sp. niveum). The first experiment was aimed to analyse genetic variation among watermelon varieties and screen varieties with high yield and/or attractive performance. The second experiment was aimed to screen varieties with good resistance against all of Fon isolates. Thirty three of watermelon varieties were subjected in the first experiment designated on Randomized Complete Block Design with three replications. Meanwhile, three isolates of Fon i.e. ‘Karawang’, ‘Lampung’ and ‘Purwakarta’ were used against 35 watermelon varieties in the second experiment designated on Completely Randomized Design with two replications. Evaluation of agronomical characters showed that based on ANOVA there were significant differences among 33 varieties for all quantitative characters. Based on all agronomical characters, Principal Component Analysis explained 75.69% total variance, whereas cluster analysis distinguished 33 varieties into three groups with 68% genetic variation. Resistance evaluation against Fon isolates showed that of 35 varieties, six varieties were demonstrated having good resistance against all of three Fon isolates. Difference was also observed within incubation period through either among varieties against the same isolate or variety against various isolates. Shortest incubation period occured on variety ‘Hitam Manis’ against isolate Karawang (< 10 days after inoculation) and the longest one occured on ‘New Dragon’ against isolate Lampung (> 23 days after inoculation). Therefore, apparently there was gene-for-gene resistance mechanism underlying through differences of genotypic reaction against the three of Fon isolates reflected in disease index and incubation periods.
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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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