Judul: Utilization of methylobacterium spp. in invigoration and seed coating technique for enhancing soybean seed vigor
Abstrak: Soybean seed deterioration is one of the problem in supplying high seed quality in tropical environtment such as Indonesia. Methylobacterium spp. for invigoration and enhancing soybean seed storage by coating technique can be used to solve this problem. The aims of the research were: (1) to find out the potency of Methylobacterium spp. for soybean seed invigoration, (2) to get Methylobacterium spp coating formulation to enhancing soybean seed storage. (3) to enumerate viable Methylobacterium spp. in coated seed during open storage. Experiments were conducted in Soil Biology Laboratory and Screen House Indonesian Soil Research Institute (ISRI), PT. East West Seed Indonesia Laboratory, Seed Technology Laboratory IPB, Bogor from November 2011 to July 2012. The research materials were soybean seed (Argomulyo), four isolates of Methylobacterium spp namely TD-TPB3, TD-J7, TD-TM3 and TD-TM1. The research consisted of two experiment (1) Methylobacterium spp application for seed invigoration in different viability, (2) Methylobacterium spp. application with seed coating at various storage period. The first experiment using Randomized Complete Block Design factorial. The first factor were six levels invigoration aplication i.e: control, soaking seed by steril water, soaking seed by TD-TPB3, soaking seed by TD-J7, soaking seed by TD-TPB3 + TD-TM3, and soaking seed by TPB-3 + TD-J7. Second factor were different seed viabiliaty, i.e: V1 (seed germination: 78 %); V2 (seed germination: 83 %); V3 (seed germination: 94 %). The second experiment using Nested Design. The first factor was storage period, i.e: 0, 1, 2, 3, 4, 5, 6 month. Second factor were 11 level formulations: control, coating with arabic gum, coating with arabic gum + tochopherol 800 ppm, coating with arabic gum + TD-TM1, coating with arabic gum + TD-TM3, coating with arabic gum + TD-TPB3, coating with arabic gum + TD-TPB3 + TD-TM1, coating with arabic gum + TD-TPB3 + TD-TM3, coating with arabic gum + peat, coating with arabic gum + TD-TPB3 + TD-TM1 + peat, coating with arabic gum + TD-TPB3 + TD-TM3 + peat. The result showed that at laboratory level, invigoration enhancing vigor index 8.9-20.6 %, and hypocotyls length 1.5-2.5 cm compare to control. In screen house experiment there was no significant improvement for vegetative stage in soybean. Coating with formula arabic gum, arabic gum + tochopherol 800 ppm, and arabic gum+TD-TM3 consistently maintain significant higher seed germination (SG) and germination rate (GR) seed viability until 6 month storage compare to control also have no significant vigor index (VI) compare to control. Coating formula with peat resulting low SG (78.3-80.7 %), whereas coating formula with Methylobacterium spp resulting higher SG (81.3-86.7 %) compare to without coating (79.3 %) after 6 month storage. Methylobacterium spp. still viable in formula coated seed until 6 month storage. Colony number decrease from 5.00 x 104 - 1.80 x 107 cfu g-1 seed to 1 x 101 - 1.14 x 102 cfu g-1seed at 6 month storage.
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Judul: he Effectiveness of Methylobacterium spp Isolate to Increase Production of Soybean (Glycine max L.).
Abstrak: Methylobacterium spp is one of bacteria that produces phytohormon which have potency to stimulate seed germination and plant growth to increase plant production. The aim of the research was to evaluate effectiveness of Methylobacterium spp and rates of fertilizer to increase soybean yield in field production. The research consisted of two experiments : (1) The effect of Methylobacterium spp application technique and rates of fertilizers on the soybean growth and production, (2) Effectiveness of Methylobacterium spp application technique to soybean yield in field production. The experiments were conducted in July 2012 to March 2013. The first experiment used Split Plot Design. The main plot was Methylobacterium spp application technique consisted of without Methylobacterium spp, seed soaking and spraying Methylobacterium spp at 15 and 30 days after planting (DAP), seed soaking and spraying Methylobacterium spp at 15 DAP and soaking seeds with Methylobacterium spp. The subplot was the rates of fertilizer N, P and K consisted of 0, 25, 50, 75 and 100% recommended rate of fertilizer (Rate of recommendation : 50 kg N ha-1, 100 kg P2O5 ha-1 dan 100 kg K2O ha-1). The second experiment used randomize complete block design. The experiment used two cultivation technologies are Methylobacterium spp and farmers. Methylobacterium spp cultivation technology used the best result of the experiment 1, seed soaking and spraying Methylobacterium spp at 15 DAP and 75% recommended rate of fertilizer. The farmers technology used 100% recommended rate of fertilizer. The results showed that seed soaking and spraying Methylobacterium spp at 15 DAP and 15+30 DAP significantly increased the age and total of flowering, total of pod , total of seed and weight of seed than without isolate application. The rate of fertilizer 50, 75 and 100% gives the same response at height of plant 56 DAP, total branches per plant and weight of seed per plant but significantly increase than without application. The seed soaking and spraying Methylobacterium spp technology and rate of fertilizer 75% significantly increased total production and seed vigour of soybean compared with the farmers technology.
Keyword: bacteria, cultivation technology, rates of fertilizer N, P and K

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