Judul: Biological responses of brown planthopper nilaparvata lugens stål (hemiptera: delphacidae) on seven rice varieties
Abstrak: Brown planthopper is one of the major pest on rice in Indonesia. Rice resistance is one of the components to control brown planthopper outbreak. The problem arises when brown planthopper could developing into new biotype that could adapt on previous resistanct varieties. In developing new resistant varieties, it is necessary to understand the responses of the brown planthopper to the various rice varieties which have different level of resistance.
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Judul: Pengujian resistansi beberapa padi lokal terhadap wereng coklat, nilaparvata lugens stal
Abstrak: Twenty local rice varieties were identified showing moderate resistance reactions (Scale 3-6) during their seedling stage to colonies of biotype-1, biotype-2 and mixture of both biotypes of Brown Planthopper (BPH) in the laboratory. The varieties were further tested during their flowering stage of development to the BPH biotypes. The aim of the experiment is to determine weather rice plants showing moderate resistance in their seedling stage are also moderately resistant when they reach flowering stage or vice verca. This is important, since experience showed that the BPH caused hopperburn in any growth stage of susceptible varieties. Varieties having moderate resistance reactions in any stage of their development would reduce the threat of BPH for cousing hopperburn. None of the varieties tested showed moderate resistance reactions in both stages of their development to the biotypes of BPH. Paya Siam 8560 was found to be moderately resistant (Scale 4.66) in its seedling stage to biotype-1, biotype-2 and mixture of both biotypes of BPH, but as the plant becomes older they become susceptible. On the other hand, Paya Rumbiah 8558 was susceptible during its seedling stage, but showed moderate resistance reactions when they reach flowering stage. Crossing of both Paya Siam 8560 and Paya Rumbiah 8558 may be nescessary to obtain plants which would be moderately resistant in both seedling as well as flowering stage of the plant. Many more local germ plasms need to be tested for moderate reactions to the BPH biotypes in both their growth stages which would reduce the chance for hopperburn by BPH.
Keyword: Tanaman inang, Hama tanaman, Varietas padi, Wereng coklat

Judul: Membran Komposit Kitosan-Zeolit untuk Aplikasi Direct Methanol Fuel Cell
Abstrak: Direct methanol fuel cell (DMFC) is a fuel cell that utilize methanol as the fuel source. The electrolyte membrane used in the DMFC system in this research was chitosan-zeolite composite membrane. The composite membrane was synthesized with chitosan-zeolite composition variation of 1:1, 1:2, 1:3, and 2:1. The membranes were analyzed by Fourier transform infrared spectrophotometer (FTIR) and scanning electron microscope, and for the specific gravity. Membrane performances were tested with methanol uptake, methanol permeability, conductivity, and potential difference in the DMFC system. The FTIR spectrum showed no formation of new functional groups inducating that the composite membrane was a result of physical mixing. Morphological analysis showed that the membrane was nonporous. Chitosan-zeolite 1:3 composite membrane had the highest specific gravity and methanol uptake, 1.4226 g/mL and 41.44%, respectively. The highest proton conductivity was showed by the 1:2 chitosanzeolite composite membrane, namely 7.2946× 10-7 S/cm. Based on this research results, chitosan-zeolite composite membrane can be applied in DMFC system.
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