Judul: Pengaruh perlakuan iradiasi sinar gamma terhadap beberapa patogen terbawa umbi bawang merah
Abstrak: Indonesia is known as shallot-producing countries, but also imported shallot in a large numbers. The high rate of import may increase the risk of entry and spread of quarantine pests from the country of origin into the territory of Indonesia. Some of those quarantine pests are Cercospora duddiae, Pseudomonas syringae pv. syringae and Erwinia carotovora subsp. atroseptica. Gamma irradiation (cobalt-60) is a developing technique of quarantine treatment for eliminating the quarantine pests. The aims of this study are to see the effectiveness of gamma irradiation for eliminating quarantine pests and its effect on tuber’s germination as well as marketable tubers, to determine the feasibility of gamma irradiation as one of quarantine treatment techniques. In this experiment, the quarantine pests were replaced with non quarantine pathogen as a model, which are C. personata, E. carotovora, and fluorescence Pseudomonads. Dose of 50 Gy shows its effectiveness in inhibiting the germination percentage of shallot up to 10.3% and increasing the percentage of marketable tubers during storage up to 8.7%. The effective doses to eliminate fluorescence Pseudomonads, C. personata, and E. carotovora were 1500 Gy, 2000 Gy, and more than 5000 Gy, respectively. But those doses, caused more than 80% un-marketable. Based on those data, gamma irradiation could not be recommended as a quarantine treatment for imported shallot.
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Judul: Perlakuan Panas pada Umbi Bawang Merah untuk Menekan Insidensi Virus di Lapangan
Abstrak: Infeksi virus merupakan salah satu kendala utama dalam produksi bawang merah. Beberapa virus tular umbi seperti OYDV, SLV, dan GCLV dapat menyebabkan penyakit semenjak tahap awal perkembangan tanaman. Salah satu metode pengendalian yang biasa digunakan untuk mengurangi infeksi virus terutama virus-virus tular umbi adalah dengan perlakuan air panas. Tujuan penelitian ini adalah untuk mempelajari pengaruh perlakuan air panas dalam menekan insidensi penyakit akibat infeksi virus di lapangan. Umbi bawang merah dari varietas ‘Bima Brebes’ dan ‘Sumenep’ diberi perlakuan perendaman air panas dengan suhu 50 OC selama 15 dan 30 menit sebelum ditanam. Untuk varietas ‘Tuk-Tuk’, digunakan true shallot seed yang langsung disemai tanpa perlakuan air panas. Insidensi penyakit diamati berdasarkan perkembangan gejala dan dikonfirmasi dengan mendeteksi virus menggunakan metode dot immunobinding assay (DIBA). Hasil penelitian menunjukkan perlakuan air panas tidak berpengaruh terhadap tinggi tanaman dan jumlah rumpun. Gejala infeksi virus dapat diamati sejak minggu pertama dan mencapai > 90% pada minggu ke 8. Gejala penyakit pada varietas Tuk-Tuk terlihat pertama kali pada minggu ke 6 dan hanya mencapai 59.3% pada minggu ke 9. Ketiga jenis virus, yaitu OYDV, SLV, dan GCLV terdeteksi pada sampel daun yang diambil pada minggu ke 7. Hasil skoring DIBA menunjukkan perlakuan air panas cenderung mengurangi titer virus pada tanaman. Titer virus pada varietas Tuk-Tuk lebih rendah bila dibandingkan dengan varietas Bima Brebes dan Sumenep. Oleh karena itu, perlakuan air panas dan penggunaan true shallot seed dapat direkomendasikan untuk mengurangi infeksi virus pada tanaman bawang merah., Virus infection is one of major constraint in shallot (Allium ascalonicum) production. Bulbborne viruses, such as OYDV, SLV, and GCLV are able to cause disease since early stage of plant development. Hot water treatment is commonly used as a control method to reduce virus infection, especially for seedborne viruses. The aim of this research was to study the effect of hot water treatment on shallot bulbs in suppressing virus incidence in field. Bulbs of ‘Bima Brebes’ and ‘Sumenep’ varieties was given hot water treatment (50 OC) for 15 and 30 min before planting, whereas true seed of ‘Tuk-Tuk’ variety was directly sown. Diseases incidence was observed based on symptom development and confirmed by virus detection using dot immunobinding assay (DIBA) method. The result showed that hot water treatment did not effect plant height and number of tillers. Diseases symptoms was readily observed on ‘Bima Brebes’ and ‘Sumenep’ since the 1st week and it reached >90% in the 8st week; whereas disease symptom on ‘Tuk-Tuk’ was observed for the 1st time in the 6st week and it only reached 59.3% in the 9st week. Three viruses, i.e. OYDV, SLV and GCLV was detected from leaf samples taken in the 7st week. DIBA’s score indicated that hot water teatment tends to reduce virus titer on the plant. Virus titer from ‘Tuk-Tuk’ was lower than those from ‘Bima Brebes’ and ‘Sumenep’. Therefore, hot water treatment and the use of true shallot seed could be recommended to reduce viral diseases on shallot.
Keyword: dot immunobinding assay, insidensi penyakit, true shallot seed

Judul: Cycle Hamilton pada Graf Lengkap, Graf Regular, dan Graf 2-Connected 4-Regular Berorder Kurang dari Sepuluh.
Abstrak: Suatu graf disebut graf Hamilton apabila graf tersebut memuat cycle Hamilton, yaitu cycle yang melewati setiap vertex tepat satu kali. Menentukan keberadaan cycle Hamilton pada suatu graf dapat menggunakan syarat cukup yang berupa teorema-teorema yang telah diperkenalkan sejak tahun 1950-an. Beberapa syarat cukup yang dibahas dalam karya ilmiah ini adalah syarat cukup yang berhubungan dengan graf lengkap dan graf regular. ,,,
Keyword: graf Hamilton, graf regular, graf lengkap, graf 2-connected 4-regular.