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INDONESIA
Indonesian Journal of Agricultural Science
Published by Kementerian Pertanian
ISSN : 1411982X     EISSN : 23548509     DOI : -
Core Subject : Agriculture,
The journal publishes primary research articles from any source if they make a significant original contribution to the experimental or theoretical understanding of some aspect of agricultural science in Indonesia. The definition of agricultural science is kept as wide as possible to allow the broadest coverage in the journal. Accredited base on Director Decree of Indonesian Institute of Science No. 816/D/2009 with acreditation No. 172/AU1/P2MBI/08/2009. IJAS is newly accredited by the Indonesian Institute of Science in 2012 (No. 473/AU2/P2MI-LIPI/08/2012) for period of 2012-2015.
Arjuna Subject : -
Articles 330 Documents
MINERALOGICAL CHARACTERIZATION AND CHEMICAL PROPERTIES OF SOILS AS A CONSIDERATION FOR ESTABLISHING SUSTAINABLE SOIL MANAGEMENT STRATEGIES Anda, Markus; Mulyani, Anny; Suparto, Suparto
Indonesian Journal of Agricultural Science Vol 13, No 2 (2012): October 2012
Publisher : Indonesian Agency for Agricultural Research and Development - MOA

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Problems of soil limiting factors affecting crop growth were not fully understood owing to little attention has been given to soil mineralogy and its association to soil chemical properties. The objective of the study was to assess soil  mineralogical and chemical properties of seven soils derived from different parentmaterials as an integrated strategic consideration to establish soil management. Field study was carried out in 2009. Soils were sampled from each horizon of profiles. Results showed that primary and secondary minerals had a strong effect on soil chemical properties. The sand fraction of soils derived from basalt, gabbro, mica schist and serpentinite was dominated by resistant minerals (quartz or opaques), leading to very limited, if any, nutrients released from parent  materials. The clay fraction was dominated by kaolinite for soils derived frombasalt, mica schist and gabbaro, and by amorphous materials for the soil derived from serpentinite resulting in low soil cation exchange capacity (CEC). For other three soils derived from volcanic tuff, volcanic basaltic andesite and volcanic ash, the easily weatherable minerals (feldspar and ferromagnesian) were dominant, suggesting the high reserved nutrients. The presence of halloysite and smectite minerals in the soil derived from volcanic tuff resulted in high soil CEC, while the dominance of amorphous materials in soils derived from volcanic basaltic andesite and volcanic ash was responsible for the low CEC. Forsoils derived from basalt, serpentinite, mica schist and gabbro, therefore, the strategic management should be directed to restore soil CEC, pH, exchangeable cations and P content. For soils derived from volcanic tuff, volcanic basaltic andesite and volcanic ash, the presence of easily weatherable minerals indicated many reserved nutrients; hence the soil management is directed for  replenishment of nutrients removed by crops.
THE EFFECT OF PICLORAM AND LIGHT ON SOMATIC EMBRYOGENESIS REGENERATION OF PINEAPPLE Roostika, Ika; Khumaida, Nurul; Mariska, Ika; Wattimena, Gustaaf Adolf
Indonesian Journal of Agricultural Science Vol 13, No 2 (2012): October 2012
Publisher : Indonesian Agency for Agricultural Research and Development - MOA

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Smooth Cayenne is the largest pineapple type cultivated in Indonesia, but its vegetative planting materials for mass propagation are limited. Somatic embryogenesis is a potential method to be applied. The aim of this study was to investigate the somatic embryogenesis regeneration under the effect of picloram and light. Callus formation was induced by picloram (21, 41 and 62 μM) added with 9 μM thidiazuron. The calli were transferred onto MS or Bac medium  enriched with N-organic compounds with or without addition of 21 μM picloram under dark or light condition. The compact calli were subcultured onto MS medium supplemented with 4.65 μM kinetin, while the friable calli were  transferred onto BIG medium (modified MS + 1.1 μM benzyl adenine + 0.9 μM indole butyric acid + 0.09 μM giberelic acid) or B medium (MS + 0.018 mM benzyl adenine). The results showed that the events of somatic embryogenesis were started from cell polarization, asymmetrical division, proembryo formation as  embryogenic tissues and friable embryogenic tissues, and embryo development. The best treatment for callus induction was 21 μM picloram. The addition of 21 μM picloram on N-organic enriched medium and the use of light condition  proliferated embryogenic calli. The N-organic enriched Bac medium and light condition yielded the highest number of mature somatic embryos (17 embryos perexplant in 2 months). The B medium was better than BIG medium to develop  somatic embryos from friable embryogenic tissues. The somatic embryogenesis method presented is potential for pineapple mass propagation and artificial seedproduction.Abstrak Bahasa IndonesiaSmooth Cayenne merupakan kultivar nenas yang banyak dibudidayakan di  Indonesia, namun ketersediaan benih untuk perbanyakan massal masih terbatas. Embriogenesis somatikadalah metode yang potensial untuk produksi bibit secara massal. Tujuan penelitian adalah untuk mempelajari pengaruh pikloram dan pencahayaan terhadap regenerasi embriogenesis somatik nenas. Kalus diinduksi menggunakan pikloram (21, 41, dan 62 μM) dan penambahan thidiazuron 9 μM. Selanjutnya, kalus dipindahkan ke media MS atau Bac yang diperkaya dengansenyawa N-organik dengan atau tanpa penambahan pikloram 21 μM dalam kondisi gelap atau dengan pencahayaan. Kalus kompak disubkultur pada media MS yang mengandung kinetin 4,65 μM, sedangkan kalus remah dipindahkan ke media BIG (MS modifikasi + bensil adenin 1.1 μM + indole butyric acid 0,9 μM + giberelic acid 0,09 μM) atau media B (MS + bensil adenin 0,018 μM). Hasil penelitian  menunjukkan bahwa tahapan embriogenesis somatik diawali dengan polarisasi sel, pembelahan asimetris, pembentukan proembrio sebagai jaringan embriogenik danjaringan embriogenik remah, serta perkembangan embrio. Perlakuan terbaik untuk induksi kalus adalah pikloram 21 μM. Penambahan pikloram 21 μM pada media yang diperkaya dengan senyawa N-organik mampu meningkatkan jumlah kalusembriogenik. Media Bac yang diperkaya senyawa N-organik dan kondisi pencahayaan menghasilkan jumlah embrio somatik dewasa terbanyak (17 embrio per eksplan dalam 2 bulan). Media B lebih baik daripada media BIG untuk regenerasi embrio somatik dari jaringan embriogenik remah. Metode embriogenesis somatik yang dihasilkan dari penelitian ini berpotensi diterapkan untukperbanyakan massal dan produksi benih nenas.
METHANE EMISSION FROM DIRECT SEEDED RICE UNDER THE INFLUENCES OF RICE STRAW AND NITRIFICATION INHIBITOR Sutriswanto, Slamet
Indonesian Journal of Agricultural Science Vol 13, No 1 (2012): April 2012
Publisher : Indonesian Agency for Agricultural Research and Development - MOA

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Incorporation of rice straw into soil is a common practice to improve soil productivity and increase inorganic fertilizer availability. However this practice could contribute to methane (CH4) emission; one of the greenhouse gases that causes global warming. Nitrification inhibitors such as neem cake and carbofuran may reduce methane emission following application of rice straw. The study was aimed to evaluate the application of rice straw and nitrification inhibitor to methane emission in rainfed low land rice system.  A factorial randomized block design was used with three replicates. The first factor is rice straw applications (5 t ha-1 fresh straw, 5 t ha-1 composted straw), and the second factor is nitrification inhibitors (20 kg ha-1 neem cake, 20 kg ha-1 carbofuran nematicide). The experiment was conducted at rainfed lowland area in Pati, Central Java during 2009/2010 rainy season. Ciherang variety was planted as direct seeded rice with spacing of 20 cm X 20 in each plot of 4 m X 5 m. The rice straw was treated together with soil tillage, whereas nitrification inhibitor was applied together with Urea application. Parameters observed were methane flux, plant height, plant biomass, grain yield, organic C content, and bacterial population in soil. The methane flux and soil organic C were measured at 25, 45, 60, 75, and 95 days after emergence. The experiment showed that composted rice straw application significantly emitted methane lower (73.2±6.6 kg CH4 ha-1 season-1) compared to the fresh form of rice straw (93.5±4.0 CH4 ha-1 season-1).  The application of nitrification inhibitors neem cake and carbofuran reduced methane emission as much as 20.7 and 15.4 kg CH4 ha-1 season-1, respectively.  Under direct seeded rice system, methane flux level relates with plant biomass as shown by linier regression of Y = 0.0015 X +0.0575 (R2 = 0.2305, n = 27).  This means that higher plant biomass produced more methane flux. The study indicates that application of nitrification inhibitors such as neem cake is more prospective in decreasing methane emission from direct seeded rice cropping because name trees are abundant in eastern parts of Indonesia.
FARMERS WILLINGNESS TO ACCEPT (WTA) FOR SUBMERGENCE RICE VARIETIES AT FLASH FLOOD AND FLOOD PRONE AFFECTED RICE AREA Manikmas, Made Oka A.
Indonesian Journal of Agricultural Science Vol 13, No 2 (2012): October 2012
Publisher : Indonesian Agency for Agricultural Research and Development - MOA

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Farmers are rational in decision making process with respect to any introduced agricultural technology. Farmers may consider the economic sacrifices in term of additional cost and potential benefit or additional income before they accept and adopt the introduced technology. This study aimed to analyze farmer’s criteria and determine explanatory variables affecting farmer’s decision to accept or to adopt submergence tolerant (Sub-1) rice varieties at flash flood and flood prone affected rice area. The study was conducted in Indramayu District, West Java, and Kayu Agung District, South Sumatra. Contingent Valuation Method (CVM) that derived Willingness to Accept (WTA) approach was exercised to analyze explanatory variables that influence farmers’ willingness to accept introduced rice varieties. The results showed that the economic cost of flooding that damaged rice was about US$7.63 million in Kayu Agung and US$11.25 million in Indramayu in every wet season planting. Farmer’s criteria used in submergence tolerant varietal evaluation varied and location specific in nature. Most of explanatory variables used in the model were significantly influenced farmers’ WTA for submergence tolerant rice varieties such as: (1) availability of seed, (2) submergence tolerant for more than 14 days, (3) high yield, (4) proffer rice taste, (5) households’ income during normal year, (6) area planted during normal year, and (7) age of farm household head. The only indicator that did not significantly influence the farmers’ WTA for the Sub-1 rice varieties was farm household income during the flood year cropping.Abstrak Bahasa IndonesiaPetani cukup rasional dalam mengambil suatu keputusan yang terkait dengan teknologi introduksi. Petani selalu mempertim-bangkan korbanan ekonomi yang mereka keluarkan sebagai konsekuensi tambahan biaya dan potensi tambahan pendapatan sebelum mereka menerima dan mengadopsi suatu teknologi introduksi. Studi ini dimaksudkan untuk menganalisis faktor yang memengaruhi keinginan petani untuk menerima atau meng-adopsi varietas padi tahan rendaman (Sub-1) pada lahan yang mengalami banjir musiman atau lahan rawa lebak. Penelitian dilaksanakan di Kabupaten Indramayu, Jawa Barat, dan Kayu Agung, Sumatera Selatan. Contingent Valuation Method (CVM) yang menggiring keinginan petani untuk menerima atau menolak suatu teknologi introduksi, diterapkan untuk menganalisis peubah penjelas yang memengaruhi keinginan petani untuk menerima atau menolak padi tahan rendaman. Hasil penelitian menunjuk-kan bahwa biaya ekonomi yang ditimbulkan oleh kedua jenis rendaman pada lahan sawah sekitar US$7,63 juta di Kayu Agung dan US$11,25 juta di Indramayu pada setiap tanam padi di musim hujan. Kriteria yang digunakan petani dalam mengevaluasi varietas padi tahan rendaman bervariasi dan bersifat spesifik lokasi. Sebagian besar peubah penjelas yang digunakan dalam model secara nyata dan positif mampu menjelaskan keinginan petani untuk menerima dan mengadopsi varietas padi tahan rendaman, seperti: (1) ketersediaan benih, (2) varietas padi toleran rendaman sampai 14 hari, (3) hasil tinggi, (4) rasa sesuai dengan selera konsumen, (5) pendapatan rumah tangga petani pada tahun normal (tidak banjir), (6) area tanam pada tahun normal, dan (7) umur kepala rumah tangga petani. Satu-satunya peubah bebas yang tidak berpengaruh nyata terhadap keinginan petani untuk mengadopsi varietas padi Sub-1 adalah pendapatan rumah tangga petani pada tahun munculnya banjir dan merendam lahan sawah.
HIGH LATEX YIELDING AND DISEASE RESISTANCE OF RUBBER CLONES IRR 200 SERIES Daslin, Aidi-; Woelan, Sekar; Pasaribu, Syarifah Aini
Indonesian Journal of Agricultural Science Vol 13, No 2 (2012): October 2012
Publisher : Indonesian Agency for Agricultural Research and Development - MOA

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Rubber clones of Indonesian Rubber Research (IRR) 200 series have been produced from intensive breeding program started in 1985. Some clones showed superior characteristics such as high latex yielding, vigorous, and disease resistant. This study aimed to test their performances in a field trial conducted since 1999 at Sungei Putih Experimental Garden, North Sumatra. The experiment was designed in a randomized block, using twelve IRR clones as treatment and PB 260 clone as control, three replications. Planting distance was 5 m x 4 m and plot size was 10 rows x 50 trees. Observations were made on girth size of the 2, 3 and 4 year-old trees, dry rubber yield following the 1/2S d/2 and 1/2S d/3.ET2.5% tapping systems, bark thickness, rings number and diameter of latex vessels, as well as leaf fall diseases intensities of 3-5 year-old trees. The results showed four IRR 200 clones, i.e. IRR 207, IRR 208, IRR 211 and IRR 220 produced high latex. Using the 1/2S d/2 tapping system, three clones with highest dry rubber yield were obtained, namely IRR 208 (49.8 g tree-1 tapping-1 or g t-1 t-1), IRR 211 (48.8 g t-1 t-1) and IRR 220 (52.0 g t-1 t-1), whereas that using the 1/2S d/3. ET2.5% tapping system, their yields were 63.2 g, 64.3 g, and 66.2 g t-1 t-1, respectively. At four year-old, these clones had girth size of 41.4-51.0 cm, girth increment 9.7-11.6 cm year-1, bark thickness 6.3-7.2 mm, latex vessel rings number 6.8-7.0, and diameter of latex vessels 23.75-26.57 mm. All of the clones were moderately resistant to Colletotrichum, Oidium and Corynespora leaf fall diseases. This study suggests that IRR 207, IRR 208, IRR 211 and IRR 220 rubber clones are suitable for commercial stake holders and the recommended tapping system is 1/2S d/3.ET2.5%.Bahasa IndonesiaKaret klon IRR (Indonesian Rubber Research) seri 200 dihasilkan melalui program pemuliaan yang intensif mulai tahun 1985. Beberapa klon menunjukkan karakteristik unggul sebagai penghasil lateks tinggi, jagur, dan tahan terhadap penyakit. Penelitian ini bertujuan untuk menguji kinerja klon pada percobaan lapangan yang dibangun tahun 1999 di Kebun Percobaan Sungei Putih, Sumatera Utara. Percobaan dirancang dalam acak kelompok dengan perlakuan dua belas klon IRR dan kontrol klon PB 260, tiga ulangan. Jarak tanam 5 m x 4 m dan luas plot 10 baris x 50 pohon. Pengamatan dilakukan terhadap ukuran lilit batang pada umur 2, 3 dan, 4 tahun, hasil karet kering dengan sistem sadap 1/2S d/2 dan 1/2S d/3.ET2,5%, tebal kulit, jumlah cincin, dan diameter pembuluh lateks. Intensitas serangan penyakit gugur daun diamati pada tanaman berumur 3 dan 5 tahun. Hasil penelitian menunjukkan empat klon karet IRR seri 200 yaitu IRR 207, IRR 208, IRR 211, dan IRR 220 menghasilkan lateks yang tinggi. Dengan sistem sadap 1/2S d/2, tiga klon memiliki hasil karet kering paling tinggi, yaitu IRR 208 (49,8 g pohon-1 sadap-1 atau g p-1 s-1), IRR 211 (48,8 g p-1 s-1), dan IRR 220 (52,0 g p-1 s-1), sedangkan menggunakan sistem sadap 1/2S d/3. ET2,5%, hasil masing-masing klon adalah 63,2 g, 64,3 g, dan 66,2 g p-1 s-1. Pada umur empat tahun, klon-klon ini memiliki ukuran lilit batang 41,4-51,0 cm, pertambahan lilit batang 9,7-11,6 cm tahun-1, ketebalan kulit 6,3-7,2 mm, jumlah cincin pembuluh lateks 6,8-7,0, dan diameter pembuluh lateks 23,75-26,57 mm. Semua klon tahan terhadap penyakit gugur daun Colletotrichum, Oidium, dan Corynespora. Dengan demikian, klon karet IRR 207, IRR 208, IRR 211, dan IRR 220 cocok dikembangkan secara komersial dan sistem sadap yang dianjurkan adalah ½S d/3.ET2,5%.
POTENTIAL USE OF ENDOPHYTIC BACTERIA TO CONTROL Pratylenchus brachyurus ON PATCHOULI Harni, Rita; Supramana, Supramana; Supriadi, Supriadi
Indonesian Journal of Agricultural Science Vol 13, No 2 (2012): October 2012
Publisher : Indonesian Agency for Agricultural Research and Development - MOA

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Pratylenchus brachyurus is an important parasitic nematode which significantly decreases quality and quantity of patchouli oil. One potential measure for controlling the nematode is by using endophytic bacteria. These bacteria also induce plant growth. This study aimed to evaluate the potential of endo-phytic bacteria to control P. brachyurus. The experiments were carried out in the Bacteriological Laboratory of the Plant Protection Department, Bogor Agricultural University, and the Laboratory and Greenhouse of the Indonesian Spice and Medicinal Crops Research Institute from April to December 2007. Endophytic bacteria were isolated from the roots of patchouli plants sampled from various locations in West Java. Antagonistic activity of the isolates were selected against P. brachyurus and their abilities to induce plant growth of patch-ouli plants. Isolates having ability to control P. brachyurus and promote plant growth were identified by molecular techniques using 16S rRNA universal primers. The results showed that a total of 257 isolates of endophytic bacteria were obtained from patchouli roots and their population density varied from 2.3 x 102 to 6.0 x 105 cfu g-1 fresh root. As many as 60 isolates (23.34%) were antagonistic against P. brachyurus causing 70-100% mortality of the namatode, 72 isolates (28.01%) stimu-lated plant growth, 32 isolates (12.47%) inhibited plant growth, and 93 isolates (36.18%) were neutral. Based on their antago-nistic and plant growth enhancer characters, five isolates of the bacteria, namely Achromobacter xylosoxidans TT2, Alcaligenes faecalis NJ16, Pseudomonas putida EH11, Bacillus cereus MSK, and Bacillus subtilis NJ57 suppressed 74.0-81.6% nema-tode population and increased 46.97-86.79% plant growth. The study implies that the endophytic bacteria isolated from patchouly roots are good candidates for controlling P. brachyurus on patchouly plants. Bahasa IndonesiaPratylenchus brachyurus adalah nematoda parasit pada tana-man nilam yang dapat menurunkan hasil dan kualitas minyak nilam. Salah satu cara pengendalian yang potensial terhadap nematoda tersebut adalah menggunakan bakteri endofit. Selain dapat membunuh nematoda, bakteri endofit juga dapat meng-induksi pertumbuhan tanaman. Penelitian bertujuan untuk  mengevaluasi potensi bakteri endofit yang berasal dari tanaman nilam untuk mengendalikan namatoda parasit P. brachyurus. Penelitian dilakukan di Laboratorium Bakteriologi, Departemen Proteksi Tanaman, Institut Pertanian Bogor, serta di  laboratorium dan rumah kaca Balai Penelitian Tanaman Rempah dan Obat, pada bulan April sampai Desember 2007. Bakteri endofit diisolasi dari sampel akar tanaman nilam dari beberapa lokasi di Jawa Barat. Isolat-isolat bakteri endofit diseleksi kemampuannya untuk membunuh P. brachyurus dan menginduksi pertumbuhan tanam-an nilam. Isolat bakteri endofit yang potensial selanjutnya diidentifikasi secara molekuler menggunakan primer universal 16S rRNA. Penelitian memperoleh 257 isolat bakteri endofit dengan kerapatan populasi 2,3 x 102 sampai 6,0 x 105  cfu g-1 berat basah akar. Enam puluh isolat (23,34%) di antaranya bersifat antagonis terhadap P. brachyurus dengan mortalitas 70-100%, 72 isolat (28,01%) dapat memacu pertumbuhan tanaman nilam, 93 isolat (36,18%) bersifat netral, dan 32 isolat (12,47%) dapat menghambat pertumbuhan tanaman. Berdasarkan hasil peng-ujian antagonis dan pemacu pertumbuhan tanaman, lima isolat bakteri, yaitu Achromobacter xylosoxidans TT2, Alcaligenes faecalis NJ16,  Pseudomonas putida EH11, Bacillus cereus MSK, dan Bacillus subtilis NJ57 dapat menekan populasi nematoda 74,0-81,6% dan meningkatkan pertumbuhan nilam 46,97-86,79%. Penelitian mengindikasikan bahwa bakteri endofit dari tanaman nilam berpotensi mengendalikan P. brachyurus pada tanaman nilam.
METHANE EMISSION FROM DIRECT SEEDED RICE UNDER THE INFLUENCES OF RICE STRAW AND NITRIFICATION INHIBITOR Wihardjaka, A.; Tandjung, S. Djalal; Sunarminto, B. Hendro; Sugiharto, Eko
Indonesian Journal of Agricultural Science Vol 13, No 1 (2012): April 2012
Publisher : Indonesian Agency for Agricultural Research and Development - MOA

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Incorporation of rice straw into soil is a common practice to improve soil productivity and increase inorganic fertilizer availability. However, this practice could contribute to methane (CH4) emission; one of the greenhouse gases that causes global warming. Nitrification inhibitors such as neem cake and carbofuran may reduce methane emission following application of rice straw. The study aimed to evaluate the application of rice straw and nitrification inhibitor to methane emission in rainfed lowland rice system. A factorial randomized block design was used with three replications. The first factor was rice straw incorporation (5 t ha-1 fresh straw, 5 t ha-1 composted straw), and the second factor was nitrification inhibitor application (20 kg ha-1 neem cake, 20 kg ha-1 carbofuran). The experiment was conducted at rainfed lowland in Pati, Central Java, during 2009/2010 wet season. Ciherang variety was planted as direct seeded rice with spacing of 20 cm x 20 cm in each plot of 4 m x 5 m. The rice straw was treated together with soil tillage, whereas nitrification inhibitor was applied together with urea application. Parameters observed were methane flux, plant height, plant biomass, grain yield, organic C content, and bacterial population in soil. The methane flux and soil organic C were measured at 25, 45, 60, 75, and 95 days after emergence. The results showed that composted rice straw incorporation significantly emitted methane lower (73.2 ± 6.6 kg CH4 ha-1 season-1) compared to the fresh rice straw (93.5 ± 4.0 CH4 ha-1 season-1). Application of nitrification inhibitors neem cake and carbofuran reduced methane emission as much as 20.7 and 15.4 kg CH4 ha-1 season-1, respectively. Under direct seeded rice system, methane flux level correlated with plant biomass as shown by linear regression of Y = 0.0015 X + 0.0575 (R2 = 0.2305, n = 27). This means that higher plant biomass produced more methane flux. The study indicates that application of nitrification inhibitors such as neem cake is prospective in decreasing methane emission from direct seeded rice cropping. 
MULTIFUNCTIONAL MUTANTS OF Azospirillum sp. WITH ENHANCED CAPABILITY OF SOLUBILIZING PHOSPHORUS, FIXING NITROGEN AND PRODUCING INDOLE ACETIC ACID Riyanti, Eny Ida; Hadiarto, Toto; Susilowati, D.N.
Indonesian Journal of Agricultural Science Vol 13, No 1 (2012): April 2012
Publisher : Indonesian Agency for Agricultural Research and Development - MOA

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Azospirillum sp. have long been known as biofertilizer for plant growth because of its capability to produce phytohormones and fix nitrogen from the atmosphere. Multifunctional Azospirillum strain Aj Bandung 6.4.1.2 isolated in 2009 from cauliflower (Brassica oleracea) rhizosphere in Lembang, Bandung, West Java, was capable of fixing nitrogen, solubilizing tricalcium-phosphate, and producing phytohormone indole acetic acid (IAA). The study aimed to modify the multifunctions of Azos-pirillum sp. for better capability of fixing N2, solubilizing P, and producing IAA using ethyl methanesulfonate and 1-methyl-3-nitro-1-nitrosoguanidine (EMS) mutagen. The study was conducted at Indonesian Center for Agricultural Biotechnology and Genetic Resources Research and Development (ICABIOGRAD) in 2010. The results showed that this strain was genetically mutagenized using EMS for better performance in solubilizing P, fixing N2 (nitrogenase activity), and producing phytohormone (IAA). The optimum concentration and the length of incubation time for the process have been determined. Nine selected mutants with increasing capability to solubilize P (determined by clear-zone formation on Pikovskaya’s medium) have been characterized for nitrogenase activities and IAA production compared to wild type Aj Bandung 6.4.1.2. The effect of mutagenesis on IAA produc-tion and nitrogenase activities varied among the mutans. Two mutants, AzM 3.7.1.16 and AzM 1.7.2.12, showed superiority in the production of IAA, while two mutants, AzM 1.5.1.14 and AzM 3.7.1.15, were superior in nitrogenase activities. The EMS mutagenesis of Azospirillum sp. showed enhanced dissolving capa-bility of unsoluble phosphate (tricalciumphosphate) and increased IAA production and nitrogenase activity.  
POTENCY OF PREDATOR (Menochilus sexmaculatus) AUGMENTATION FOR WHITE FLY (Bemisia tabaci) MANAGEMENT AND ITS EFFECT ON GEMINI VIRUS INFESTATION ON TOMATO Setiawati, W.; Gunaeni, N.; Uhan, T. S.; Hasyim, A.
Indonesian Journal of Agricultural Science Vol 13, No 1 (2012): April 2012
Publisher : Indonesian Agency for Agricultural Research and Development - MOA

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Bemisia tabaci (Gen.) (Homoptera: Aleyrodidae) is one of the most serious pests on tomato. It is mainly controlled by chemi-cal means, requiring some 25 sprays during the average growing season. The extensive and repeated use of insecticides has dis-rupted the natural balance between this pest and its natural enemies. In this study, Menochilus sexmaculatus F. was evalu-ated as a possible biological control agent of B. tabaci and its effect on Gemini virus infestation. The study was conducted at the experimental station of the Indonesian Vegetables Research Institute (IVeGRI) in Lembang, West Java (1,250 m above sea level) from August to December 2008. The experimental plots consisted of 0.35 ha of tomato (± 100 m2 per plot) and spatially separated with four rows of maize (a minimum of 1 m) inter-plot distance to prevent cross-contamination among plots. The experiment was arranged in completely randomized block design with eight treatments and four replications. M. sexmaculatus were released at 24 days after planting. The treatments were designed according dosages and schedules at three released populations (i.e. 10 predators per plot, 20 predators per plot, and 10 predators per plot at vegetative stage followed by 20 predators per plot at generative stage); two places of release (center and edge of the plot); and two schedules of release (weekly and biweekly). Efficacy of the predator was measured in terms of the density of B. tabaci, both before and after release of the predator and its effect on Gemini virus infestation. The result indicated the potential use of M. sexmaculatus to control B. tabaci and its effect on Gemini virus infestation on tomato. Reductions in B. tabaci populations and subsequent tomato yields were significant. B. tabaci population in plots receiving 10 predators showed 73.62% and 75.75% reductions by the end of experiment. The incidence and intensity of Gemini virus were consistently and significantly lowest and tomato yield gain was observed when 10 predators were released at weekly intervals. It is suggested that release of M. sexmaculatus against B. tabaci on tomato may be offered as an alternative solution to increase implementation of biologically-based B. tabaci management.
IMPACT OF BRACHIARIA, ARBUSCULAR MYCORRHIZA, AND POTASSIUM ENRICHED RICE STRAW COMPOST ON ALUMINIUM, POTASSIUM AND STABILITY OF ACID SOIL AGGREGATES Hafifa, Bariot; Sabiham, Supiandi; Anas, Iswandi; Sutandi, Atang Sutandi; Suyamto, Suyamto
Indonesian Journal of Agricultural Science Vol 13, No 1 (2012): April 2012
Publisher : Indonesian Agency for Agricultural Research and Development - MOA

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Abstract

Acid soil is commonly grown with cassava, which in general, tolerate low soil  fertility and aluminum (Al) toxicity. However, without any improvement efforts such soil will become worse. Intercropping cassava with Brachiaria decumbens (BD) which adapts to acid soil and tolerates low fertility soils as well as application of arbuscular mycorrhiza (AM) and organic matters are among the important efforts to rehabilitate this soil. The experiment was conducted to  examine the impact of BD, AM, and potassium (K) enriched rice straw compost on exchangeable Al, available K, and stability of soil aggregates. Experiment was arranged in a completely randomized design with three factors and three replications. The first factor was BD as cassava intercropping, the second factor was AM, and the third factor was 2 t ha-1 rice straw compost enriched with 0 kg, 50 kg, 100 kg, and 200 kg KCl ha-1. Brick pots (1 m length x 1 m width x 0.45 m depth) filled with Kanhapludult soil was used for growing cassava in which row of BD was planted at 60 cm from cassava stem. K-enriched rice straw compost and AM (10 g per stem) were applied around cassava stem at 2 and 12 days after planting, respectively. BD was cut every 30 days and the cutting was returned to the soil. Soil exchangeable Al was analyzed at 0, 3, 6 and 9 months after planting (MAP), while Al and K contents as well as aggregate stability were measured at 6 MAP. The results showed that planting BD decreased 33% exchangeable Al, which means that the root exudates of this grass was effective in detoxifying Al3+. Treatment of BD and/or in combination with AM was effective in preserving K added to the soil, increasing total polysaccharides, and improving soil aggregate stability. This indicated that planting BD and applying AM and Kenriched rice straw compost improved acid soil fertility, and therefore can be recommended in cassava cultivation.

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