Judul: Pengaruh infeksi virus mosaik kedelai pada berbagai umur tanaman kedelai (glycine max (L.) merrill) varietas orba dan americana terhadap hasil biji
Abstrak: Penelitian ini bertujuan mempelajari pengaruh infeksi virus mosaik kedelai yang diinokulasikan pada berbagai umur tanaman kedelai varietas Orba dan Americana. Kombinasi perlakuan yang diperiksa disusun secara berfaktor 2 x 2 x 4. Faktor pertama adalah inokulasi, faktor kedua adalah varietas kedelai, dan faktor ketiga adalah umur tanaman waktu diinokulasi. Pengaruh infeksi virus mosaik kedelai ditentukan oleh adanya interaksi umur tanaman waktu diinokulasi dan varietas kedelai. Respons kedelai Orba dan Americana terhadap infeksi virus mosaik kedelai tidak sama. Pengaruh infeksi virus mosaik kedelai terhadap tanaman kedelai dapat dilihat berdasarkan sifat pertumbuhan dan hasil biji. Ternyata infeksi virus mosaik kedelai dapat menghambat pertumbuhan dan mengurangi basil biji, terhambatnya pertumbuhan dan berkurangnya hasil tampak nyata bila inokulasi dilakukan pada umur tanaman muda sampai menjelang berbunga.
Keyword: Soybean mosaic virus;, Cereals;, Soybean leaf curl;, Soybean chlorosis;, Bogor Agricultural University;

Judul: Interaksi antara virus mosaik kedelai (SMV) dengan virus bantut kedelai (SSV) pada kedelai
Abstrak: Penelitian ini bertujuan untuk mengetahui pengaruh (interaksi) infeksi ganda SMV dengan SSV pada kedelai. Penelitian dilakukan di rumah kaca Jurusan Hama dan Penyakit Tumbuhan, Fakultas Pertanian, Institut Pertanian Bogor. Pada penelitian ini dilakukan 4 macam perlakuan yaitu kontrol, inokulasi SMV, inokulasi SSV dan inokulasi ganda SMV + SSV. Masing-masing perlakuan dilakukan 10 kali ulangan. Virus dari sumber inokulum diinokulasikan secara mekanik pada tanaman umur dua minggu dengan cairan perasan. Parameter-parameter yang diamati meliputi periode inkubasi, periode pembungaan pertama, tinggi tanaman dan berat kering biji. Hasil penelitian ini menunjukkan untuk bahwa pemunculan gejala tercepat pada tanaman dengan perlakuan ganda yaitu dengan periode inkubasi selama 6 hari, dan yang terakhir tanaman dengan perlakuan SMV yang periode inkubasinya 7.4 hari. Sedangkan pemunculan bunga. pertamanya, perlakuan ganda SMV + SSV paling lama dan berbeda nyata dengan kontrol. Demikian juga pengaruh perlakuan virus terhadap tinggi tanaman. Tanaman dengan perlakuan ganda dan SSV terhambat pertumbuhannya dengan persen penghambatan sebesar 38% untuk perlakuan ganda, 36,71% untuk perlakuan SSV dan 9.89 untuk perlakuan SMV. ...
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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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