Judul: Ketahanan terhadap hawar daun bakteri dan keragaan produktivitas padi sawah yang ditanam tunggal dan campuran
Abstrak: The core of Indonesian agricultural development policy is to meet the demand of rice as staple food. The improved varieties which have been used still faced constraints such as abiotic and biotic stress. One of the important biotic stress is Bacterial Leaf Blight disease caused by Xanthomonas oryzae pv. oryzae. According to the previous research, mixture varieties planting could reduce disease intensity and increase the yield. The aim of this research was to find out the genotype that resistance to BLB, yield stability, genetic variability and other characters stability on single and mixture planting. The experiment used 17 genotypes as treatments which consisted of 7 cultivars and 10 cultivar mixtures with different resistance to BLB background. The trial was designed in Randomized Complete Block Design and replicated three times. The trial was conducted during two seasons in Majalengka and Pacitan. The characters observed were Bacterial Leaf Blight spreading, plant height, number of panicle per hill, number of well-filled grain per panicle, number of unfilled grain per panicle, number of total grain per panicle, 1000 grains weight, well-filled grain percentage, yield per ha and sink size. The disease spreading data was used to analyze the first appearance of disease, disease incidence, disease severity and Area Under Disease Progress Curve (AUDPC). The yield data was used to analyze yield stability and genetic parameters, while agronomic characters data was used to analyze the difference between two seasons and between single and mixture genotype using t test. According to the result of analysis, there was no difference between single and mixture genotype on the first appearance of disease, disease incidence, disease severity and AUDPC. The result of combine and stability analysis showed that genotype, season and their interactions influenced the yield; and the stable, unstable and specific single and mixture genotype could be determined. According to t test to other characters, there was no difference between single and mixture genotype. Based on the result of the analysis, the effect of mixture to reduce the Bacterial Leaf Blight disease and to increase the yield has not been known yet.
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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: 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. Suatu graf lengkap berorder 𝑛������ ≥ 3 dan graf r-regular berorder 𝑛������ ≤ 2𝑟������ + 1 merupakan graf Hamilton, Karena kedua graf tersebut memuat cycle Hamilton. Selanjutnya, syarat cukup tersebut digunakan untuk menentukan keberadaan cycle Hamilton pada graf 2-connected 4- regular berorder kurang dari 10.
Keyword: graf Hamilton, graf regular, graf lengkap, graf 2-connected 4-regular