Judul: Pembiakan Streptomyces katrae pada Formulasi Beras dan Jagung serta Pengaruhnya Terhadap Daya Tumbuh Benih padi
Abstrak: Streptomyces have a potential to be growth promotion agent and biocontrol of plant disease. The limitation for wide use at the farmer level is the problem of mass production. The objective of this study was to evaluate the rice and corn formulation as media for mass production of Streptomyces katrae and the effect of its application on rice seed growth. Both of rice and corn formulation was inoculated with isolates of S. katrae and incubated until 20 days. Seed coating is application to see effect of S. katrae on rice seed growth. Three days after its inoculation, mycelial had grown on all formulation. Fifteen days after incubation, the higher population S. katrae is FB2 (90% rice + 10% mushroom baglog waste) and FJ2 (90% corn + 10% mushroom baglog waste) with total population 124.8 x 107 cfu and 107.6 x 107 cfu. The effect of S. katrae had seen influence at ten days after rice seed planting on compos sterile, with root length, bud length and reduction of population X. oryzae pv. oryzae, but not influence with germination. Both rice and corn formulation can be an alternative substrate for low cost mass production of S. katrae inoculum.
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Judul: Studi Keefektifan Formulasi Spora Bacillus Subtilis Sebagai Agens Pengendali Hayati Penyakit Hawar Daun Bakteri dan Hawar Pelepah Serta Pemicu Pertumbuhan Pada tTanaman Padi:
Abstrak: In controlling rice diseases, most farmers still rely on chemical pesticide as the solution. However, because of high cost and negative effects of chemical pesticide, biocontrol is one of alternative solutions. Bacillus subtilis is a model of biocontrol agents to control many plant diseases, because its ability to produce antimicrobial and plant growth promoting substances. This research aimed to examine the effectiveness of Indonesian isolate of B. subtilis spore formulation through seed treatment and foliar spray with different frequencies and concentrations to control bacterial leaf blight (Xanthomonas oryzae pv. oryzae) and sheath blight (Rhizoctonia solani) diseases of rice. The influence of the formulation application to plant growth and other microbes was evaluated. The experiment was conducted in greenhouse and field with factorial experimental design. Seed treatment, concentration and frequency of application and its interaction effectively suppressed bacterial leaf blight and sheath blight diseases, increased plant growth and reduced yield loss. The concentration at 2% is recommended for applying the formulation. The interval of application at 1 and 2 week showed equal effect to disease suppression and increased yield. Application of B. subtilis spore formulation increased yield of Ciherang, Cisantana, and Sintanur as much as 26,3%, 18,5%, and 15,4% respectively. Application of the formulation gave no significant effect to microbe diversity in the field.
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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