Judul: Performance and Productivity of Potato (Solanum tuberosum L.) Granola Variety from Five Generations of Tuber Seed.
Abstrak: Produktivitas kentang di Indonesia masih dapat ditingkatkan melalui penggunaan benih bermutu. Kelas benih merupakan hal yang penting, mengingat kentang diperbanyak secara vegetatif. Penelitian ini bertujuan mengetahui pengaruh penggunaan generasi benih yang berbeda terhadap keragaan dan produktivitas kentang. Penelitian dilaksanakan di Desa Aek Natolu Jaya, Kecamatan Lumban Julu, Kabupaten Toba, Provinsi Sumatera Utara pada bulan November hingga bulan Maret 2020. Rancangan yang digunakan dalam penelitian ini adalah Rancangan Kelompok Lengkap Teracak (RKLT) faktor tunggal yaitu perlakuan dari lima generasi kentang varietas Granola yaitu G0, G1, G2, G3, dan G4 dengan tiga ulangan. Hasil penelitian menunjukkan perlakuan G0, G1, dan G2 memiliki keragaan yang sama dan merupakan keragaan yang terbaik berdasarkan keragaan tinggi dan diameter batang serta memiliki produktivitas terbaik. Produktivitas mulai menurun pada perlakuan G3 dan G4. Jumlah umbi per tanaman yang paling tinggi adalah perlakuan G0 dan G1. Grade umbi A hanya terdapat pada perlakuan G2, hal ini menunjukkan bahwa G2 lebih cocok dijadikan sebagai benih sebar. Perlakuan G0, G1, dan G2 juga menghasilkan grade umbi yang lebih baik dibandingkan G3 dan G4., The Potato productivity in Indonesia can still be increased through the use of quality seeds. Seed class is important in potato production as it is propagated vegetatively. This study aimed to determine the effect of different seed generations on potato performance and productivity. The study was carried out in Aek Natolu Jaya village, Lumban Julu sub-district, Toba Regency, North Sumatra Province from November to March 2020. The design used in this study was a single factor Randomized Complete Block Design (RCBD). The treatments were five generations of Granola potato, G0, G1, G2, G3, and G4 with three replicates. The results showed that treatment G0, G1, and G2 had the same performance and achieved the best performance based on the height and diameter of the stem and had the best productivity. The productivity started to decrease in the G3 and G4 treatments. The highest number of tubers planted was achieved by G0 and G1 treatments. Grade A tubers were only found in the G2 treatment, this indicated that G2 was more suitable to be used as extension seed propagule. G0, G1, and G2 treatments also produced better tuber grades than G3 and G4.
Keyword: decrease, extension seed, grade, quality, vegetative

Judul: Preliminary Result Test of Potato Genotype (Solanum tuberosum L.) in Garut District, West Java
Abstrak: Kentang (Solanum tuberosum L.) merupakan salah satu sumber karbohidrat yang diminati masyarakat, tetapi produksi dan produktivitas nasional masih rendah karena penyediaan benih bermutu masih kurang. Upaya untuk meningkatkan produksi kentang adalah dengan mengembangkan varietas baru berdaya hasil tinggi. Penelitian ini bertujuan untuk mengevaluasi daya hasil beberapa genotipe kentang IPB di Kabupaten Garut, Jawa Barat. Penelitian dilaksanakan di Desa Girijaya, Kecamatan Cikajang, Kabupaten Garut, Jawa Barat pada bulan November 2020 sampai Maret 2021. Penelitian menggunakan Rancangan Kelompok Lengkap Teracak (RKLT) factor tunggal yaitu genotipe dan tiga ulangan sebagai kelompok. Bahan tanam yang digunakan yaitu genotipe kentang PKHT-2020-006, PKHT-2020-010, PKHT-2020-012, PKHT-2020-016, PKHT-2020-017, PKHT-2019-021, serta kentang varietas medians dan granola sebagai pembanding. Hasil penelitian menunjukan bahwa genotipe PKHT-2020- 012 dan PKHT-2019-021 memiliki produktivitas lebih tinggi dari varietas pembanding. Genotipe lain yang memiliki produktivitas tidak berbeda dengan varietas pembanding adalah genotipe PKHT-2020-010., Potatoes (Solanum tuberosum L.) are one of carbohydrates source which is interested, but its national production and yield are still low. Efforts to increase potato production are by developing new varieties with higher yield. This study aimed to evaluate the yield potential of IPB genotypes potato in Garut district, West Java. The study was conducted in Girijaya Village, Cikajang District, Garut Regency, West Java in November 2020 to March 2021. This study uses a completely randomized Complete Group Design (RKLT) namely genotypes and three replications as a group. The planting material used are the potato genotype PKHT-2020-006, PKHT-2020-010, PKHT-2020-012, PKHT-2020-016, PKHT2020-017, PKHT-2019-021, as well as Medians and Granola potato varieties as a comparison. The results showed that genotypes of PKHT-2020-012 and PKHT2019-021 had the highest productivity than the comparison varieties. The others genotype that have productivity not different with comparison varieties is genotype of PKHT-2020-010.
Keyword: genotype, productivity, yield potential trial

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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