Judul: Induksi Kalus Jeruk Siam Triploid dan Transformasi Genetik pada Jeruk Siam (Citrus nobilis L.).
Abstrak: This study aims to obtain the best medium composition for callus induction of triploid tangerine from different kind of explant and regeneration of transformant citrus callus. This study is divided into 3 activities. The first aimed to induce embryogenic callus of triploid tangerine with explant from internodes, nodes, and leaves isolated from in vitro triploid tangerine buds. The explants were cultured in medium MS + MW vitamins + EM 500 mgL-1suplemented with BA 1 mgL-1, 2 mgL-1 and 3 mgL-1. The second, to introduce the gene constructs containing a selection marker (gus gene and kanamycin antibiotic) vector A. tumefaciens to triploid tangerine embryogenic callus. The third, to regenerate embryogenic callus transformant candidates in several formulations of regeneration medium. Transformant callus grown on media containing MS vitamins and MW with the addition of organic matter EM 500 mgL-1 and 10; 20; and 30% of coconut milk. Transformant callus that have been through the proliferation is regenerated on MS medium with a combination of Plant Growth Regulator:0.01 mgL-1IAA, 0.01 mgL-1 BA, 0.01 mgL-1 TDZ and 0.01 mgL-1 Kinetin. The results showed that the optimal concentration of BA for callus induction was 3 mgL-1, while different types of explants not give different results. Frequention of antibiotics application to sterilized the A. tumefaciens bacteria from callus showed the best results when done everyday. The best callus growth results of transformant callus occurs in medium MS containing vitamin MW with the addition of organic material EM 500 mgL-1. The combination of medium used for regeneration of transformant tangerine callus has not succesful yet in regenerating callus into planlet.
Keyword: Antibiotics, BA concentration, medium composition, organic matter, vitamins

Judul: Study Regeneration of Tengerine Citrus Batu 55 (Citrus reticulata) Through Somatic Embryogenesis Path Way
Abstrak: The global world market of citrus fruit that is consumed in fresh form to the current needs to fill a category of fruit that do not have seeds, easy to peel and has an attractive color (pigmented). Tangerine citrus Batu 55 is one of the mainstay of fresh fruit horticulture. Tangerine citrus Batu 55 has superior character who naturally have had so distinguished by citrus Siam but the characters are not as good as tangerine imports. Somatic embryogenesis is an important tool for supplying new varieties to be used cultivar genetic improvement programs in citrus, this technology has been extensively used and has many important implications. The objective of this research is to produce somatic embryos of Tangerine citrus Batu 55 from nucellar embryo. The research comprised: embryogenic callus induction, callus prolifertation, maturation of somatic embryo, germination of somatic embryo, shoot multiplication, roots induction, chromosome counting, acclimatization and grafting. The results showed that the medium of Murashige & Tucker + 3 mg/l BAP + 1 mg/l 2,4-D + 500 mg /l malt extract increased the percentage of the callus formation up to 40% after 4 weeks with total number of pre-embryos (PEM ) 31.0. The medium proliferation used was MS with the addition of vitamin Morell & Wetmore (MW) +3 mg/l BAP+300 mg/l casein hydrolisat. These medium improved callus diameter up to 2.3 mm after 4 weeks cultured. Maturation of embryos was obtained by transferring globular structure in the medium MW + 2.5 mg/l ABA + 500 mg/l malt extract. These medium increased the percentage of mature somatic embryo up to 98% after 4 weeks cultured. Somatic embryos up to 84% germinated when the cotyledons grown in the medium MW + 2.5 mg/l GA3. The shoot multiplication containing MW medium + 7 mg/l biotin +500 mg/l malt extract was able to produce the highest percentage of shoot multiplication up to 86 %. The root induction containing MS medium + 3 mg/l IBA was able to produce the highest percentage of root induction up to 86%. Acclimatization of plantlets with roots increased survival rate up to 90% after 5 weeks acclimatization.
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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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