Judul: Pengaruh aplikasi bakteri perakaran pemacu pertumbuhan tanaman pada tiga genotipe cabai (Capsicum annum L.) terhadap pertumbuhan tanaman serta kejadian penyakit penting cabai
Abstrak: In Indonesia, chilli was an important vegetable commodity refer to production area as well as it’s value, but production of chilli in Indonesia still very low. The low production was caused by a lack of proper cultivation techniques, seed quality, and pest and plant disease. Important disease that can decrease the production of chilli includes antrachnose disease, bacterial wilt, mosaic and mottle virus in chilli. The disease controlling effort that were recently developed and relatively safe for the environment, using Plant Growth-promoting Rhizobacteria (PGPR). The objective of this study was to determine the effect of PGPR usage, that were P. fluorescens PG01 isolates, B. polymixa BG25 and a mixture of both isolates (PG01 + BG25) against agronomic characters and incidence of important diseases in the three genotypes of chilli (IPB C5, C10 IPB, and Kopay) on the field. The experiment was performed from February until November, 2009 on farmer land were located on Desa Cibatok I, Kecamatan Cibungbulang, Kabupaten Bogor. The experiment was arranged in split plot design, were randomly treated with bacterial group as main plots and genotypes as subplots. Four levels main plots were PGPR treatments isolates PG01, BG25, PG01 + BG25, and without PGPR treatment as a comparison. The three subplots were C10 IPB, C5 IPB, and Kopay. In the experiment there were 12 treatment combinations, each treatment consisted of three replications, so there are 36 experimental units. Each experimental unit consisted of 20 plants, with a total 720 plants were tested. PGPR treatments significantly influenced the plant height and number of branches, but gave no significant effect on leaves number. The highest growth improvement on vegetative phase was occurred by the mixed bacterial treatment (PG01 + BG25). IPB C10, C5 genotypes and varieties of IPB Kopay have different agronomic characteristics measured on plant height, number of branches and number of leaves. PGPR treatment did not affect significantly to crop production and disease incidence (antraknosa, bacterial wilt, TMV, CMV, and ChiVMV). Antrachnose infections most commonly found in Kopay varieties, while the bacterial wilt infection occurs more frequently in genotypes IPB C5.
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Judul: The Effects of Biocontrol Application on Production of Four Varieties of Chilli Pepper (Capsicum spp.) for Industries
Abstrak: Cabai rawit merupakan komoditas yang penting bagi masyarakat Indonesia. Penelitian ini bertujuan mengetahui pengaruh aplikasi biokontrol terhadap karakter produksi pada empat varietas cabai rawit sehingga didapatkan rekomendasi varietas cabai dengan karakter produksi terbaik dan agen biokontrol terbaik. Penelitian dilaksanakan pada bulan Desember 2018 sampai dengan bulan Juli 2019 di Kebun Percobaan 2 PKHT (Pusat Kajian Hortikultura Tropika) Institut Pertanian Bogor, Tajur, Bogor dan di Laboratorium Pasca Panen, Departemen Agronomi dan Hortikultura, Fakultas Pertanian IPB. Rancangan percobaan yang digunakan adalah Split Plot RKLT (Rancangan Kelompok Lengkap Teracak) dua faktor. Petak utama adalah varietas cabai rawit yang terdiri dari empat taraf yaitu Rinta (R1), Kara (R2), Lentera (R3), dan Dewata (R4). Faktor kedua menjadi anak petak adalah perlakuan biokontrol yang terdiri dari empat taraf yaitu tanpa biokontrol (P0), Prima Gard (P1), PGPR Rhizomax (P2), dan kombinasi antara Prima Gard dengan Rhizomax (P3). Karakter produksi varietas Rinta, Kara, Lentera dan Dewata dapat ditingkatkan dengan memberikan perlakuan Rhizomax secara tunggal atau dikombinaksikan dengan Primagard. Varietas Lentera memiliki karakter produksi terbaik diikuti oleh varietas Kara. Produktivitas cabai rawit varietas Lentera pada penelitian ini mencapai 11,07 ton ha-1. Perlakuan biokontrol juga efektif menekan kejadian penyakit yang menyerang selama penelitian berjalan., Cayenne pepper is an important commodity for the people of Indonesia. This study aimed to determine the effects of biocontrol applications on the production of four varieties of cayenne pepper so that the recommendations regarding chili varieties with the highest production and the best biocontrol agent could be obtained. The research was carried out from December 2018 to July 2019 at the PKHT 2 Experimental Station (Center for Tropical Horticulture Studies), IPB University, Tajur, Bogor and at the Post-Harvest Laboratory, Department of Agronomy and Horticulture, Faculty of Agriculture, IPB University. The experimental design used was a two-factor split plot randomized complete block design. The main plot was the variety of cayenne pepper consisting of four levels, namely Rinta (R1), Kara (R2), Lentera (R3), and Dewata (R4). The second factor being a subplot was the biocontrol treatment consisting of four levels, namely without biocontrol (P0), Prima Gard (P1), PGPR Rhizomax (P2), and the combination of Prima Gard and Rhizomax (P3). The production of the Rinta, Kara, Lentera and Dewata varieties can be increased by giving Rhizomax treatment alone or in combination with Primagard. Lentera variety has the highest production followed by Kara variety. The productivity of Lentera chili varieties in this study reached 11,07 tons ha-1. The biocontrol treatment was also effective in suppressing the incidence of disease during the study.
Keyword: Plant Growth Promoting Rhizotobacter (PGPR), Pseudomonas sp., Bacillus sp., Cryptococcus sp.

Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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