Judul: Pelestarian secara In Vitro melalui Metode Pertumbuhan  Minimal pada Beberapa Genotipe Ubi Jalar (Ipomea  batatas(L) Lam)
Abstrak: Peningkatan produksi ubi jalar salah satunya adalah melalui penggunaan varietas unggul. Strategi pemuliaan untuk membentuk varietas ubi jalar yang unggul langkah awalnya adalah koleksi. Pemuliaan tanaman dapat dilakukan jika tersedia keragaman genotipe untuk berbagai tujuan pemuliaan. Genotipe-genotipe perlu dilestarikan baik secara konvensional maupun secara in vitro. Untuk itu koleksi menjadi sangat penting dalam pembentukan varietas. Koleksi plasma nutfah termasuk pelestarian plasma nutfah. Pelestarian plasma nutfah dapat dilakukan secara in vitro. Pelestarian plasma nutfah in vitro jangka pendek biasa disebut pertumbuhan lambat karena pertumbuhan planlet ditekan untuk sementara. Dalam pelestarian in vitro jangka pendek ini diharapkan tanaman pertumbuhannya lambat namun tidak mati.
Keyword: Metode Pertumbuhan Minimal, Ubi Jalar, Ipomea batatas, Hyponex, air kelapa, in vitro

Judul: Produksi Bibit Ubi Jalar (Ipomoea batatas L.) melalui Metode Pemotongan Umbi dan Penggunaan Giberelin
Abstrak: Penggunaan kembali stek tanaman ubi jalar untuk proses budidaya dapat meningkatkan risiko penyebaran hama, penyakit, serta penurunkn hasil. Produksi tunas dari umbi telah banyak digunakan oleh petani untuk menghindari kasus tersebut. Penelitian ini bertujuan untuk mengevaluasi pengaruh aplikasi giberilin dan metode pemotongan umbi untuk produksi tunas. Penelitian dilakukan dalam Rancangan Acak Lengkap (RAL) dua faktorial di Cikabayan Bawah Greenhouse, Institut Pertanian Bogor. Hasil penelitian menunjukkan bahwa tunas bisa tumbuh dari bagian pangkal, tengah atau ujung dari umbi yang dipotong. Aplikasi kontrol dan giberelin tidak menghasilkan jumlah bibit yang berbeda nyata. Metode pemotongan umbi menghasilkan jumlah tunas yang lebih tinggi dibandingkan umbi utuh. Umbi yang dipotong menjadi dua bagian dianggap lebih efisien daripada tiga bagian.
Keyword: ubi jalar, umbi, bibit, tunas, giberelin

Judul: Thermal Characteristics and Dynamics of Tropical Cyclone over Western North Pacific Ocean: A Case Study of Typhoon Songda (Chedeng) 2011
Abstrak: The frequent occasion of Tropical Cyclone (TC) over Western North Pacific (WNP) Ocean lies from 10˚N to 26˚N and 121˚E to 170˚E. Sources of TC development come from warm ocean temperature where latent heat is released during condensation processes and subsequently concentrated in the boundary layer. Relative humidity at 850-700 hPa is responsible to produce the most intense storm. Meanwhile, weak vertical wind shear between 850-200 hPa is one of the dynamical factors that lead to the development of TC. Pressure level of 850-200 hPa is chosen to minimize the thermodynamic effect in the lower troposphere. Typhoon Songda (Chedeng in the Philippines) or TSC lasted from May 18th to 30th, 2011 and strengthened into powerful Super Typhoon stage between May 24th and 27th. Long curving track and the exhibition of all sequences of TC life cycle, TSC is then considered as an ideal case of TC. The objective of the study with case of TSC is to investigate the role of thermal characteristics and dynamics on TC intensity. The research is carried out by using Advanced Research of Weather Research and Forecasting model (WRF ARW model) version 3.3. Two domains are employed in the model. The first domain situate from 02˚N to 40˚N and 118˚E to 149˚E and cover spatial resolution () of 33.1 km. The second domain situate from 09˚N to 27˚N and 119˚E to 132˚E with of 11 km. Timestep of the model () is 120 seconds. The model is supported by the following physical parameterization, i.e., Yonsei University Scheme (YSU) in the boundary layer, Kain-Fritsch scheme (KF) in the cumulus, and WRF Single-Moment 3-class scheme in the microphysics. Initial meteorological condition prior to the formation of the cyclone is generated using WRF ARW standard-release model. Sensitivity of the model output is obtained from a selected single-parameter change scenarios, namely, 10 % to 20 % decrease and increase of wind shear initial data at 850-200 hPa, and by 10 % to 20 % decrease of relative humidity initial data at 850-700 hPa. The result showed that the negative correlations between wind shear and intensity are found in wind shear scenarios. Wind shears of 10 ms-1 which lead to strengthening of the wind intensity in the early period of Typhoon development are found in wind shear scenarios. The effect of wind shear changes on wind intensity is statistically significant in the 20 % wind shear scenarios. During mature stage, weak wind intensity occurred when wind shear increase as given in the WRF standard-release and the 20 % decreasing scenario. Different situation is found in the 20 % increasing scenario where wind shear tend to weak and lead to strong wind intensity at this stage. Meanwhile, the reduction of moisture supply at 850-700 hPa resulting from 20 % decreasing relative humidity play a major role in the weakening of wind intensity and reduces mechanical energy of the cycle process as much as 300 J kg-1.
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