Teguh Santoso

Isolasi dan Identifikasi Entomopatogen Hirsutella citriformis (Speare) dan Potensi Miselianya sebagai Sumber Inokulum untuk Pengendalian Wereng Cokelat (Nilaparvata lugens Stål.)

Hirsutella citriformis merupakan salah satu jamur entomopatogen potensial untuk wereng batang cokelat (WBC), tetapi belum banyak dimanfaatkan karena konidianya sulit diperbanyak sehingga perlu dicari propagul alternatif. Penelitian ini bertujuan mengidentifikasi isolat H. citriformis yang menginfeksi WBC dan menguji efektivitas miselianya sebagai alternatif inokulum konidia dalam pengendalian biologis WBC. Identifikasi Hirsutella dilakukan berdasarkan karakter morfologis dan molekuler dan berdasarkan sekuen internal transcribed spacer (ITS). Konidia dan miselia pada berbagai konsentrasi diaplikasikan pada nimfa WBC instar 2–3 dengan cara penyemprotan. Hasil penelitian menunjukkan bahwa berdasarkan karakter morfologis, isolat jamur entomopatogen asal Bogor yang menyerang WBC di lapangan adalah H. citriformis. Salah satu isolat (Bgr 0716) telah diidentifikasi berdasarkan sekuen ITS dan terkonfirmasi sebagai H. citriformis. Aplikasi miselia isolat Bgr 0716 efektif mengendalikan WBC dengan nilai lethal time 50% (LT50) selama 13,3 hari, tidak jauh berbeda dari nilai LT50 konidia yang terjadi dalam waktu 12,8 hari. Nilai lethal concentration 50% (LC50) miselia sekitar 2,303 g/l, sedangkan nilai LC50 untuk aplikasi konidia adalah sebesar 2,5 × 105 konidia/ml. Dengan nilai LT50 dan LC50 yang relatif rendah tersebut, miselia layak untuk di-aplikasikan dalam skala luas karena produksinya lebih mudah dan cepat dibanding dengan produksi konidia. Oleh karena itu, miselia H. citriformis dapat menjadi propagul aktif sebagai alternatif konidia untuk pengembangan biopestisida efektif terhadap WBC.

Peningkatan Efikasi Cendawan Lecanicillium lecanii untuk Mengendalikan Telur Hama Kepik Coklat pada Kedelai

Aromatic rice is popular for its aroma, taste, and texture. The chemical compound of 2-Acetyl-1-pyrrolina (2AP) contributes to the pandan leaf-like aroma, while the hexanal compound is used as an indicator of rancidity in rice. Grains of three aromatic rice varieties, namely Mentik Wangi, Pandan Wangi, and Sintanur were milled in three degree of milling, i.e., 100, 90, and 0% (brown rice). The milled rice and the brown rice were then stored in hermetic bags and plastic bags for 4 months at room temperature. Chemical composition of the packed and stored rice grains were determined by the proximate analysis, including moisture content, ash content, fat content, protein content, and amylose content. The analysis was conducted at the beginning and the end of month of storage. Consumer preference test of the packed rice was done by the hedonic test. Moisture, ash, protein and fat contents during storage were still in the standards range. Compared to the amylose content prior to storage, the textures of the cooked rice after four months of storage remained fluffier or became less fluffy. The aroma, tenderness, texture, flavor, and overall attributes, judged by the panelists, Mentik Wangi was the most favored, followed by Sintanur and Pandan Wangi. Both hermetic bag and plastic bag gave no different effects on the stored rice quality and on the consumer preferences.The presently available cytoplasmic male sterile lines (CMS) commonly used to develop rice hybrids in Indonesia are susceptible to major pests and diseases. Research was conducted to develop new cytoplasmic male sterile lines which are highly resistant to major pests and diseases. Two new cytoplasmic male sterile rice lines, GMJ4A and GMJ5A, were developed using backcross method, derived from crosses of BP455G-PN-13-2-1-1-10-MR-3-1 and B11005E-MR-4-2-1, which were identified as completely sterile on a test cross nursery. The following season, sterile F1 generations were successively backcrossed until stable sterile plants were obtained in 2006. Seeds of the two cytoplasmic sterile lines were mass produced at Muara, Bogor, in 2006. GMJ4A and GMJ5A are resistant to bacterial leaf blight patotipe IV and VIII. Both lines are resistant to brown plant hopper in the green house test with scores of 1 to 3. The hybrid combinations involving GMJ4A and GMJ5A were evaluated in an observational yield test at Muara during dry season of 2007 and at Kuningan in dry season 2009. The level of grain yield heterosis were better than the check varieties. These two lines are expected to be used as a replacement for the existing CMS lines.Nutrient uptake capacity is an important factor for increasing rice yield. A high nutrient uptake capacity is expected to produce a high rice yield. Research was conducted at Anjir Serapat Barat Village (Land type A), and Anjir Serapat Timur Village (Land type B) in the Kapuas Timur District, Central Kalimantan, during the planting season (PS) of 2006. The trial was arranged in a randomized complete block design with five treatments of three replications. The treatment consisted of 5 high-yielding rice varieties (IR66, IR64, Kapuas, Margasari, and Martapura) and each set was planted at two land types (Land types A and B). The variables observed were the N, P, K, Ca, and Mg uptakes by rice plants. Results showed that nutrient uptake capacities of rice plants were affected by rice varieties and by land types. The highest nutrient uptake capacity was found on variety Margasari grown on Land type A, which was equal to 55.2 kg K/ha, 47.6 kg N/ha, 19.7 kg P/ha, 19.7 kg Ca/ha, and 3.11 kg Mg/ha, followed by variety Martapura grown on Land type A, which was equal to 51.8 kg K/ha, 46.1 kg N/ha, 17.9 kg Ca/ha, 17.1 kg P/ha, and 9.7 kg Mg/ha. The lowest nutrient uptake capacity was found on variety Kapuas grown on Land type B, which was equal to 21.3 kg K/ha, 17.0 kg N/ha, 5.2 kg Ca/ha, 5.0 kg P/ha, and 2.8 kg Mg/ha. Differences on nutrient uptake capacity may influence the biomass and grain yield.