Judul: Peran bakteri kitinolitik dan fungi mikoriza arbuskular dalam pengendalian busuk pangkal batang kelapa sawit
Abstrak: Basal stem rot (BSR) is the most serious disease of palm oil that caused by Ganoderma boninense Pat. The objectives of these researches were to find chitinase-producing bacterial which inhibit G.boninense growth and to determine the relationship between mycorrhizal and chitinolytic bacterial in controlling the BSR. The experimenthals were conducted in laboratory, secreen house dan fields. The research activities were: (i) exploration of chitinolytic bacterial as antagonistic agents of pathogens (ii) evaluate the pathogenicity, index chitinolitic of the chitinolytic bacterial and their antagonism effect against G. boninense, (iii) study on the application of chitinolytic bacterial and AMF in controlling the oil palm BSR through split plot experimenthal design. There were seven isolate B13, B14, B16, B42, Al11, TB41 and L34 have been selected as the best chitinolase-producing bacterial and they were not pathogenic to plants. The study showed that selected bacterial have differences on chitinolytic index. All of them suppressed the growth of G. boninense above 95% in vitro antagonism test using dual culture method on liquid media. However the antagonism test on PDA only isolate of AL11, TB41 and L34 had higher antagonism capacity against the pathogen. The severity of basal stem rot that expressed by the root necrotics were reducted since the oil palm seedling showed high degrees of mycorrhizal root colonization. The application of combination of chitinolytic bacterial and AMF suppressed the disease severity (95%) higher compare to the single one (55% - 7
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Judul: Isolation, Identification, and Media Formulation of  Endophytic Bacteria to Limit Ganoderma Fungus Attacks on Oil Palm
Abstrak: Ganoderma boniense merupakan cendawan patogen yang menyebabkan penyakit busuk pangkal batang (BPB) pada tanaman kelapa sawit. Penelitian ini mengkaji suatu alternatif dalam mengendalikan G. boninense melalui pemanfaatan agens pengendali hayati (APH) yang lebih ramah lingkungan daripada penggunaan fungisida komersial. Seleksi bakteri endofit sebagai APH dilakukan melalui isolasi bakteri dari akar kelapa sawit, mengukur persen zona hambatan terhadap isolat G. boninense secara in vitro, dan uji hipersensitif pada tanaman tembakau. Isolat bakteri endofit terpilih A2 dan C5 memiliki daya hambat terhadap G. boninense berturut-turut sebesar 35% dan 47%. Kedua isolat tersebut teridentifikasi secara molekuler berturut-turut sebagai bakteri Lysinibacillus xylanilyticus (99,85%) dan bakteri Aeromonas hydrophila (99,64%). Bakteri endofit terpilih diformulasikan ke dalam formulasi kompos, tepung, dan cair. Ketiga jenis formula dapat mempertahankan viabilitas sel sampai dengan 106 cfu/ml serta lebih stabil dan adaptif pada formulasi cair dengan kepadatan berkisar (8,0–9,0)×106 cfu/ml pada akhir minggu pengamatan dibandingkan formulasi lainnya., Ganoderma boninense is a pathogenic fungus that causes basal stem rot (BSR) diseases in oil palm plantations. This research examined an alternative in controlling G. boninense through the use of biological control agents (BCAs) which was more environmentally friendly than the use of commercial fungicide. Endophytic bacteria as BCAs were selected by isolating bacteria from oil palm roots, measuring the percent zone of inhibition against G. boninense based on in vitro test, and presenting hypersensitivity test on tobacco plant. Selected endophytic bacterias namely A2 and C5 had inhibiton against G. boninense of 35% and 47%, respectively. Those isolates were identified molecularly as Lysinibacillus xylanilyticus (99,85%) and Aeromonas hydrophila (99,64%), respectively. The selected endophytic bacterias were formulated in compost, flour, and liquid formulation. Those three types of formula could maintain cell viability up to 106 cfu/ml and are more stable also adaptive in liquid formulation within a range of (8,0–9,0)×106 cfu/ml at the end of the observation compared to other formulations.
Keyword: basal stem rot (BSR), endophytic bacteria, Ganoderma boninense, media formulation, oil palm

Judul: Approximation of the Median of Poisson Distribution Using the Relation of Poisson-Gamma Distribution
Abstrak: A major drawback of median is that median cannot usually be defined in closed form, even in the cases where their distribution functions are known. This study gives an approximation of the closed form for the median of the Poisson distribution by using the relation of Poisson-Gamma distribution. The approximation uses elementary techniques based on the monotonicity of certain sequences involving tail probabilities of the Poisson distribution and the Central Limit Theorem. Furthermore, a closed form expression for the mean absolute deviation 􀜧|􀜰􀰒 􀵆 􀜯􀝁􀝀􁈺􀜰􀰒􁈻| is also studied. The median is relevant because of the fact that it minimizes the mean absolute deviation of a Poisson random variable (􀜰􀰒􁈻 by considering median as central tendency.
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