Judul: Perlakuan Benih dan Perendaman Akar Bibit dengan Agens Hayati untuk Mengendalikan Serangan Xanthomonas oryzae pv. oryzae serta Meningkatkan Pertumbuhan Tanaman Padi di Rumah Kaca
Abstrak: Xanthomonas oryzae pv. oryzae (Xoo) causing bacterial leaf blight (BLB) in rice is a seed-borne pathogen, could reduce yield by 60%. This experiment was conducted to evaluate the effect of seed treatment and root dipping on BLB incidence and vegetative growth of rice plant in the greenhouse. The experiment was arranged in a split plot-randomized complete block with four replications. The main plots were seed treatments (6 levels) and the subplots were root dipping (8 levels). Matriconditioning was conducted using burned rice hull 30 mesh as carrier or media with ratio of seed:carrier:solution of bactericide or biological agents = 1:0.8:1.2 (g:g:ml) at 25 0C for 30 h. Root dipping was conducted for 1 h. The results showed that seed treatment with matriconditioning + Pseudomonas diminuta A6 + Bacillus subtilis 5/B improved seed germination, vigor index, germination rate, and reduced the BLB incidence. Matriconditioning + P. diminuta + B. subtilis was able to increase plant height without root dipping treatment. However, the seed treatment should be followed by root dipping on 3 week-old seedling in order to increase plant dry weight. Seed treatment using matriconditioning + P. diminuta + B. subtilis and followed by root dipping with P. diminuta + B. subtilis (106 cfu/ml) effectively and efficiently increased plant dry weight. Seed treatment with matriconditioning + P. diminuta + B. subtilis or root dipping with P. diminuta + B. subtilis (106 cfu/ml) produced the highest number of tillers up to 4 weeks after transplanting. Severities of BLB up to 4 weeks after transplanting was low (1.7%-2.5%). Seed treatment using matriconditioning + 0.2% bactericide or roots dipping with P. diminuta + B. subtilis (108 cfu/ml) reduced the BLB incidence effectively at vegetative phase.
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Judul: Potensi Beberapa Bakteri Penghambat Pertumbuhan Xanthomonas oryzae pv. oryzae Penyebab Penyakit Hawar Daun Bakteri pada Tanaman Padi
Abstrak: Bacterial leaf blight (BLB) disease caused by plant pathogenic bacteria Xanthomonas oryzae pv. oryzae (Xoo) could lead to death of rice plants. Control of plant pathogenic bacteria can be performed using biological control agents. The aim of this research was to study the inhibitory ability of eight isolates of biocontrol bacteria against Xanthomonas oryzae pv. oryzae (Xoo) under greenhouse conditions. Isolates of biological agents used in the study were obtained from IPB Culture Collection (IPBCC), Department of Biology, IPB and microbial gene bank collection of Indonesian Center for Agriculture Biotechnology and Genetic Resources (BB Biogen), consisting of Pseudomonas aeruginosa C32a and C32b, P. fluorescens ATCC 13525 Pf , Serratia marcescens E31, Bacillus sp. I.5, B. cereus I.21 and II.14, and B. firmus E65 isolates. The methods used in the research i.e. hypersensitivity test, antagonistic test of biocontrol bacteria to Xoo, and in vivo application of biological agents in the greenhouse condition. Hypersensitivity test on tobacco plants using C32a and C32b inoculums showed characteristics of slightly leaf yellowing but did not cause necrosis. Injection using Xoo inoculum showed necrosis on tobacco leaves. Antagonist isolates i.e. C32a, C32b, Pf, I.21, and I.5 showed inhibitory activity against Xoo, whereas others isolates did not show inhibitory activity. In greenhouse experiments IR 64 rice plants were sprayed with biological control agents (107cfu/ml) at 7 days, 14 days, 28 days, and 42 days after planting. The results showed that C32a isolate could suppress better the lesion length of BLB than that of chemical control (copper sulphate). Growth measurement of rice plants were assessed on plant height, number of tillers, panicle number and grain weight. Rice plants spraying treatment with isolates E65, E31, C32a, C32b, I.21, Pf, and I.5 showed no difference with control of sterile distilled water. Spraying with each suspension isolate of I.21, E31, C32a, Pf, and C32b indicated no different in the panicle number, in addition rice production was higher in C32a, Pf, C32b, and I.21 treatments. Spraying with C32a isolates produced the highest grain production compared with that of other isolates.
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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.