Judul: Perlakuan Agens Hayati untuk Mengendalikan Hawar Daun Bakteri, Meningkatkan Pertumbuhan Tanaman dan Produksi Benih Padi
Abstrak: Healthy rice seed (free of Xanthomonas oryzae pv. oryzae (Xoo)) could be produced by prevention of Xoo infection from the seed source and the plant. Xanthomonas oryzae pv. oryzae causes bacterial leaf blight (BLB) in rice. The objectives of the research were to evaluate biological agent treatments in controlling BLB and increasing plant growth and seed production of rice. The research consisted of two parts. The first part was aim to obtain the rhizosphere and phyllosphere biological agents capable of controlling Xoo. The first experiment in the first part conducted to isolate the virulent Xoo. The second experiment was a retest for antagonism of rhizobacteria collection against the isolated Xoo which would be used in seed treatments. The third experiment was isolation and antagonism test of phyllosphere bacteria against Xoo to be used in spraying the plants. The second part of this study was the evaluation of biological agent treatment (seed treatment and plants spraying) effects in controlling BLB disease and improving plant growth and seed production. The first experiment was conducted in the greenhouse and the second one in the field using the same experimental design (randomized block design with two factors) and three replications. Seed treatments (first factor) consisted of negative control, positive control, streptomycin sulfate 0.2%, Pseudomonas diminuta A6 + Bacillus subtilis 5B, matriconditioning + streptomycin sulphate 0.2%, and matriconditioning + P. diminuta A6 + B. subtilis 5B. Spraying plants (second factor) consisted of untreated control, streptomycin sulphate 0.2%, biological agent F112, biological agent F198, and biological agent F57. The first experiment from the first part of these studies resulted virulent Xoo isolated from ooze. The second experiment confirmed that P. diminuta A6 + B. subtilis 5B indicated high antagonism against the Xoo. The third experiment produced phyllosphere isolates F112, F198, and F57 showing high antagonism against the Xoo. The first experiment in the second part of these studies showed that matriconditioning + P. diminuta A6 + B. subtilis 5B improved seed germination from 93.6% to 96.9%, plant height from 70.9 cm to 76 cm, plant dry weight from 1.35 g to 1.91 g as compared to positive control. Spraying plants using biological agent F112 increased plant dry weight from 1.40 g to 1.78 g as compared untreated control. Meanwhile, matriconditioning + P. diminuta A6 + B. subtilis 5B followed by spraying plants with biological agent F112 reduced the BLB severity. The second experiment showed that matriconditioning + P. diminuta A6 + B. subtilis 5B improved seedling dry weight. Matriconditioning + P. diminuta A6 + B. subtilis 5B and spraying plants with biological agents F112 controlled BLB and increased plant growth. However, all treatments were not able to increase healthy seed production, these may be due to population of the biological agents applied was not optimum yet.
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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: Closed Knight’s Tour pada Papan Catur Berbentuk Persegi Panjang dengan Ukuran Maksimal 8 × 8
Abstrak: Closed Knight’s Tour merupakan langkah kuda yang mengunjungi setiap kotak pada papan catur tepat satu kali dengan langkah kuda berawal dan berakhir pada kotak yang sama. Graf yang terbentuk dari closed knight’s tour dinotasikan sebagai graf G(m,n), dengan m adalah banyaknya baris dan n adalah banyaknya kolom. Graf tersebut memuat Hamiltonian cycle. Sebuah graf terhubung G adalah graf bipartite jika dan hanya jika graf tersebut tidak memiliki cycle dengan panjang ganjil. Papan catur yang memenuhi syarat cukup untuk memiliki closed knight’s tour adalah papan catur berukuran 5 × 6, 5 × 8, 6 × 6, 6 × 7, 6 × 8, 7 × 8, dan 8 × 8.
Keyword: bipartite, closed knight’s tour, hamiltonian cycle, knight’s tour, teori graf