Judul: Improvement on shallot genotype for high yielding and purple blotch disease resistance
Abstrak: The problems of increasing shallot production include the use of low yielding, as well as pest and disease susceptible varieties. Purple blotch disease is one of shallot diseases that may cause up to 100% yield loss. Breeding of shallot has been hindered by narrow genetic variation among parental genotypes. Therefore, it is inevitable to explore novel sources of genetic variation that can be used to develop high yielding and purple blotch disease resistant shallot varieties. Effort to increase genetic variability can be done through crossing and mutation. The objectives of this study were: (1) to obtain shallot genotypes that high yielding and resistant to purple blotch disease, (2) to know the morphological and physiological characteristics of high yielding shallot for selection, (3) to determine general combining ability (GCA), specific combining ability (SCA) and heterosis of some shallot genotypes, (4) to study the genetic variability of the genotypes resulted from the crossing, (5) to evaluate the resistance of the genotypes to purple blotch disease, as well as their anthocyanin contents. The result showed that: (1) three mutants (G2-06-1, G3-06-2, and G2-01-2) were observed to be high yielding and resistant to purple blotch disease, (2) high yielding shallot genotypes had a rapid growth, moderate bulb and bulblets number, greater leaf diameter, and greater bulb productivity per hill, (3) high yielding genotypes were characterized by greater root growth was observed and for the upper biomass was observed compared to the low yielding genotypes, (4) shallot genotypes that have a high GCA are: Tiron and Timor, (5) shallot genotypes from crosses of SCA and heterosis effect are high between the Kuning/Tiron, Timor/Bima Juna, Tiron/Timor and Kuning/Sibolangit, (6) that based on RAPD marker, the mutants could be grouped into three class, and (7) anthocyanin content of purple blotch resistance mutant was higher than the susceptible one.
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Judul: Varietal Impact on Growth, Yield, and Water Requirements of Shallot (Allium cepa L. var. aggregatum) in Dryland Cultivation
Abstrak: Bawang merah (Allium cepa L. var. aggregatum) merupakan komoditas hortikultura yang mempunyai prospek pasar yang sangat baik sehingga termasuk ke dalam komoditas unggulan nasional. Penggunaan varietas yang merupakan salah satu cara untuk meningkatkan produktivitas bawang merah. Penelitian ini bertujuan mengetahui pengaruh dari penggunaan empat varietas bawang merah terhadap pertumbuhan, hasil panen, dan kebutuhan air pada tanaman bawang merah yang ditanam di lahan kering. Penelitian dilakukan di Kebun Percobaan Sawah Baru IPB, Dramaga, Bogor, Jawa Barat pada bulan Februari hingga April 2023. Penelitian dilakukan berdasarkan rancangan lengkap kelompok teracak (RKLT) dengan faktor tunggal. Perlakuan dalam penelitian ini adalah diamati adalah 4 varietas bawang varietas yaitu Bima Brebes, Bauji, Tajuk,dan SS Sakato. Hasil penelitian menunjukkan perlakuan varietas berpengaruh sangat nyata terhadap peubah tinggi tanaman pada 2 MST dan 3 MST, jumlah tunas pada 2 MST, 3 MST, 5 MST, dan 6 MST, jumlah daun pada 2 MST dan 4 MST, dan jumlah umbi. Seluruh varietas memberikan hasil yang baik untuk ditanam di lahan kering Bogor. Varietas Bauji merupakan varietas dengan proyeksi produktivitas per hektar tertinggi namun membutuhkan air yang lebih sedikit dari tanam hingga panen dibandingkan varietas Tajuk dan SS Sakato. Jumlah daun berpengaruh terhadap nilai evapotranspirasi, Shallot (Allium cepa L. var. aggregatum) is a horticultural commodity with excellent market prospects, thus being classified as a national superior commodity. The use of varieties is one way to enhance shallot productivity. This research aims to determine the influence of using four varieties of shallots on growth, harvest yield, and water requirements of shallot plants cultivated in dryland. The research was conducted at the Sawah Baru IPB Experimental Garden, Dramaga, Bogor, West Java, from February to April 2023. The research was based on a completely randomized block design with a single factor. The treatments in this study consisted of four observed shallot varieties: Bima Brebes, Bauji, Tajuk, and SS Sakato. The results of the research indicate that the variety treatment significantly influenced the plant height variable at 2 and 3 weeks after planting (WAP), the number of shoots at 2 WAP, 3 WAP, 5 WAP, and 6 WAP, the number of leaves at 2 WAP and 4 WAP, and the number of bulbs. All varieties showed good results for cultivation in dryland in Bogor Regency. The Bauji variety emerged as the most promising in terms of projected productivity per hectare, requiring significantly less water from planting to harvest compared to the Tajuk and SS Sakato varieties. The number of leaves influenced the evapotranspiration value.
Keyword: evapotranspirasi, curah hujan, produktivitas

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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