Judul: Response of Various Groundnut Varieties (Arachis hypogaea L.) to After-ripening Period and Breaking Seed Dormancy Treatment
Abstrak: Penelitian ini bertujuan untuk mempelajari respon beberapa varietas kacang tanah (Arachis hypogaea L.) terhadap perlakuan pematahan dormansi selama periode 6 minggu after-ripening, dan mendapatkan metode pematahan dormansi yang efektif. Percobaan ini dilaksanakan di Laboratorium Ilmu dan Teknologi Benih, Departemen Agronomi dan Hortikultura, IPB mulai November 2021 sampai Maret 2022. Terdapat dua percobaan dengan Rancangan Acak Lengkap menggunakan rancangan lingkungan Rancangan Petak Terbagi (Split Plot Design). Percobaan 1 menggunakan sembilan varietas (Hypoma 1, Takar 2, Tuban, Kancil, Kelinci, Pelanduk, Garuda, Zebra, Gajah) sebagai petak utama, dan periode after ripening sebagai anak petak. Setelah panen benih dikeringkan hingga mencapai kadar air 7–14 %, disimpan dalam kemasan plastik pada suhu rata-rata 28 °C selama 0, 2, 4, dan 6 minggu (periode after-ripening). Percobaan 2 menggunakan sembilan varietas (sama seperti percobaan 1) sebagai petak utama, dan perlakuan pematahan dormansi sebagai anak petak. Perlakuan pematahan dormansi terdiri atas kontrol (tanpa perlakuan), pelembapan awal substrat pengecambahan dengan KNO3 0,2%, dan pemanasan benih pada suhu 40 °C selama 72 jam. Selama periode 6 minggu after-ripening benih kacang tanah semua varietas belum mengalami patah dormansi. Perlakuan pemanasan benih pada suhu 40 °C selama 72 jam saat 6 minggu after ripening merupakan metode paling efektif mematahkan dormansi benih kacang tanah varietas Kancil, Kelinci, Zebra dan Gajah., This research aimed to study the responses of several peanut (Arachis hypogaea L.) cultivars to the treatment of breaking dormancy up to 6 weeks after ripening and find an effective method of breaking dormancy. The experiment was conducted at IPB Seed Storage and Seed Quality Testing Laboratory from November 2021 until March 2022. Two experiments were arranged in a Completely Randomized Design with a Split Plot environmental design. Experiment 1 used nine varieties (Hypoma 1, Takar 2, Tuban, Kancil, Kelinci, Pelanduk, Garuda, Zebra, and Gajah) as the main plot and the after-ripening period as sub-plots. After harvesting, the seeds were dried to a moisture content of 7–14% and stored in plastic packaging at an average temperature of 28 °C for 0, 2, 4, and 6 weeks (after-ripening period). Experiment 2 used nine varieties (same as experiment 1) as the main plot and the treatment of breaking dormancy as sub-plots. The dormancy-breaking treatments consisted of control (without treatment), moistening the germination substrate initially with 0.2% KNO3, and heating the seeds at 40 °C for 72 hours. During the 6-weeks after the ripening of peanut seeds, all varieties have not broken dormancy. Dormancy breaking treatment by heating seeds at 40 °C for 72 hours 6 weeks after-ripening was the most effective method of breaking the dormancy of peanut seeds cv. Kancil, Kelinci, Zebra and Gajah.
Keyword: germination, heating 40 °C, KNO3, peanut seed dormancy

Judul: Pematahan Dormansi Benih Kacang Bambara (Vigna subterranean L. Verdc.) pada Beberapa Periode After-Ripnening dengan Perlakuan Suhu Tinggi dan KNO3
Abstrak: Pengujian mutu benih kacang bambara (Vigna subterranean L. Verdc.) di laboratorium sering terkendala oleh sifat dormansi benih. Penelitian ini bertujuan mempelajari periode after-ripening benih kacang bambara serta mendapatkan metode pematahan dormansi yang efektif pada benih kacang bambara lanras Tasikmalaya warna testa hitam. Penelitian dilaksanakan bulan Maret hingga Juli 2019 di Laboratorium Penyimpanan dan Pengujian Benih, IPB. Penelitian disusun menggunakan rancangan tersarang (nested) RAL dengan metode pematahan dormansi tersarang di dalam periode after-ripening. Faktor periode after-ripening terdiri atas delapan taraf, yaitu 0,1, 2, 3, 4, 5, 6, dan 7 Minggu Setelah Penyimpanan (MSP). Faktor metode pematahan dormansi terdiri atas empat taraf, yaitu tanpa perlakuan, stratifikasi suhu 50 °C selama 10 menit, skarifikasi KNO3 1% selama 24 jam, dan stratifikasi suhu 50 °C selama 10 menit dilanjutkan skarifikasi KNO3 1% selama 24 jam. Hasil penelitian menunjukkan pada 0 MSP benih tanpa perlakuan menghasilkan viabilitas dan vigor tinggi, terutama dengan nilai tolok ukur daya berkecambah sebesar 92.3% meingindikasikan bahwa tidak ada after-ripening pada benih kacang bambara lanras Tasikmalaya warna testa hitam. Perlakuan perendaman KNO3 1% selama 24 jam dapat menurunkan viabilitas dan vigor benih berdasarkan tolok ukur daya berkecambah dan kecepatan tumbuh.
Keyword: stratifikasi, Tasikmalaya, testa hitam, viabilitas, vigor

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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