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: The Effect of Applications Methylobacterium spp to Improvement of Soybean Vigour and Production
Abstrak: Methylobacterium spp is one of bacteria that produces phytohormon which have potency to stimulate seed germination and plant growth. The objective of this research was to study the effectiveness of Methylobacterium spp isolates in improving vigour and seed production of soybean. The Research conducted since September 2010 until April 2011. The research consisted of two experiments : (1) The effect of application Methylobacterium spp bacteria isolates to soybean seed germination. The research materials are six soybean varieties i.e : Sinabung, Kaba, Tanggamus, Anjasmoro, Grobogan dan Burangrang and four isolates Methylobacterium spp i.e: TD-J2, TD-K2, TD-TPB3, NTB-K1 and control (aquades); (2) The effect of application techniques Methylobacterium spp to soybean production. The research consisted of six level : 1) without seed soaking isolate + foliar spraying at 10 DAS + 20 DAS, 2) seed soaking isolate + foliar spraying at 10 DAS + 20 DAS; 3) seed soaking isolate; 4) splashing isolate to soil at 10 DAS + 20 DAS; 5) sterile soil isolate + splashing isolate to soil at 10 DAS + 20 DAS; and 6) control (water splashing). The results showed that Methylobacterium spp soaking in TD-K2 isolate on Kaba increased vigour index 17.33% (from 72% to 89.33%) and TD-J2 isolate increased speed of germination 9.49%/etmal (from 31.74 % etmal to 41.23 %/etmal). Application techniques of Methylobacterium spp with TD-TPB3 isolate on Kaba using seed soaking isolate + foliar spraying at 10 DAS + 20 DAS increased growth and production of soybean.
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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