Judul: Deteksi Virus yang Menginfeksi Kentang (Solanum tuberosum L.) di Jawa Barat
Abstrak: Symptoms of viral infection were found in the center of potato cultivations in West Java (Rancabali, Pengalengan, and Bayongbong). However the viruses associated with these symptoms had been unknown yet. The conducted research aims to detect and identify the viruses molecularly. Fifty leaf samples were randomly collected from symptomatic potato plants of 50 samples at each location. Paramaters measured were symptoms, disease incidence, and viral DNA sequences which were predominantly found. Disease incidence was determined by serological tests using PVY, PVX, PVS, and CMV antiserum. While nucleic acid was amplified by RT-PCR and DNA sequencing. The result showed that the symptoms were found vary in potato leaves, such as mosaic, vein clearing, vein banding, rugose, and leaf malformation. Disease incidence of PVY, PVX, PVS, and CMV in Rancabali were 28%, 0%, 0%, and 28%, in Pengalengan were 80%, 24%, 2%, and 82%, and in Bayongbong were 82%, 0%, 6%, and 74%, respectively. RT-PCR using specific DNA primers successfully amplify PVY and CMV coat protein gene from Bayongbong each approximately size 801 bp and 657 bp. The homology of nucleotide and amino acid of PVY from Bayongbong against PVY isolates from the other countries ranged from 89.5-99.7% and 92.0-100%. The highest homology was closely to PVYNTN from China and Japan. Whereas the homology of nucleotide and amino acid of CMV from Bayongbong against CMV isolates from the other countries ranged from 87.6-96.9% and 86.9-93.7%. The highest homology was closely to CMV strain Soybean stunt (SS) from Bogor (Indonesia). Both of viruses strain (PVYNTN and CMVSS) and PVS were the first reported in potato crops in Indonesia.
Keyword: PVY., potato, CMV

Judul: Pengaruh cucumber mosaic virus (CMV) dan potato virus Y (PVY) pada tanaman tomat (lycopersicum esculentum Mill.)
Abstrak: Penelitian ini bertujuan untuk mengetahui pengaruh infeksi tunggal CMV, PVY, serta infeksi ganda CMV dan PVY terhadap penurunan hasil tanaman tomat. Penelitian dilaksanakan pada bulan Maret sampai Mei 1997 di rumah kaca dan Laboratorium Virologi Tumbuhan, Jurusan Hama dan Penyakit Tumbuhan, Fakultas Pertanian, lnstitut Pertanian Bogor. lnokulum CMV dan PVY diperoleh dari Laboratorium Virologi Tumbuhan, Jurusan Hama dan Penyakit Tumbuhan, Fakultas Pertanian, lnstitut Pertanian Bogor. Perbanyakan inokulum CMV dan PVY dilakukan pada berturut-turut Nicotiana glutinosa, dan N. tabacum cv White Barley melalui inokulasi secara mekanik. Hasil perbanyakan ini digunakan sebagai sumber inokulum yang diinokulasikan ke tanaman uji yaitu tomat yang berumur satu bulan. lnokulasi secara mekanik dilakukan dengan menggunakan cairan perasan sumber inokulum dengan perbandingan jaringan sakit dan buferfosfat 0.01 M ( pH 7) 1:3 (berat/volume). Sebelum di inokulasi, daun tomat ditaburi Carborundum secara merata dan cairan perasan dioleskan secara perlahan-lahan dengan menggunakan tusuk gigi yang dililiti kapas.
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Judul: Ongkos irregularitas sebuah graf
Abstrak: Tulisan ini mengkaji bagaimana cara mcngubah sualu graf menjadi graf yang irregular, yaitu dengan menambahkan beberapa edge pacta graf asal. Untuk sebuah graf G, didefinisikan ongkos irregularitas ic(G) yaitu jumlah minimum tambahan edge sedemikian sehingga menjadi Multigraf H yang merupakan multigraf G irregular. Akan ditentukan ongkos irregularitas dari graf regular, graf mendekati regular, dan graf mendekati irregular.
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