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: Growth and Production of G0 Potato (Solanum tuberosum L.) Seed Tuber of IPB CP3 in Greenhouse and Screenhouse in the Medium Altitude
Abstrak: Kentang (Solanum tuberosum L.) adalah komoditas hortikultura yang memiliki nilai ekonomi tinggi. Indonesia masih mengimpor benih kentang karena produksi benih dalam negeri tidak mencukupi. Keterbatasan produksi benih kentang industri, salah satunya kentang varietas IPB CP3 disebabkan oleh keterbatasan luas lahan di dataran tinggi. Untuk meningkatkan produksi benih, perlu dilakukan pemanfaatan lahan di dataran menengah dengan menggunakan varietas yang sesuai. Penelitian ini bertujuan membandingkan pertumbuhan dan produksi benih umbi G0 kentang varietas IPB CP3 dari stek yang ditanam di dalam rumah kaca dan rumah kasa di dataran menengah. Stek pucuk berumur 2 minggu setelah tanam yang sudah berakar ditanam pada polybag yang berisi media cocopeat. Setiap satuan percobaan terdiri atas 20 tanaman dengan 3 ulangan, sehingga di dalam rumah kaca atau rumah kasa terdapat 60 tanaman. Panen dilakukan pada umur 90 hari setelah tanam. Parameter yang diamati adalah tinggi tanaman, jumlah buku, jumlah daun, jumlah umbi, bobot basah serta bobot kering tajuk dan umbi. Hasil penelitian menunjukkan bahwa rumah kaca dan rumah kasa memberikan pengaruh yang signifikan terhadap pertumbuhan dan produksi benih umbi G0 kentang IPB CP3. Pertumbuhan tanaman dan produksi benih umbi G0 kentang varietas IPB CP3 di dalam rumah kasa secara signifikan lebih baik daripada rumah kaca., Potato (Solanum tuberosum L.) is a horticultural commodity with high economic value. Indonesia is still importing potato seeds due to insufficient seed production. The lack of seed tuber production for potato chips is due to the limited land area in high-altitude regions. It is necessary to produce seed tubers in the medium altitude with suitable varieties. The study aims to compare the growth and production of G0 potato seed tubers of IPB CP3 variety planted in greenhouse and screenhouse in the medium altitude. Two weeks old of the rooted shoot-cuttings were transferred into polybags containing cocopeat media. Each experimental unit consists of 20 plants with 3 replications, therefore there are 60 plants in greenhouse and screenhouse. The potato seed tubers were harvested at 90 days after planting. The parameters observed were plant height, number of nodes, number of leaves, number of tubers, fresh and dry weight of the plant shoot and tubers. The research showed that greenhouse and screenhouse had a significant effect on the growth and production of G0 potato seed tubers of IPB CP3. The growth and production of G0 potato seed tubers of the IPB CP3 variety in screenhouse is significantly better than that in greenhouse.
Keyword: greenhouse, potato chips, screenhouse, shoot-cuttings, sipitri

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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