Judul: Host Suitability of Silverleaf Whitefly, Bemisia tabaci (Genadius) (Hemiptera:Aleyrodidae) on Several Chili Pepper Genotypes and Varieties
Abstrak: Kutukebul, Bemisia tabaci (Genadius) (Hemiptera:Aleyrodidae), merupakan salah satu hama penting tanaman cabai B. tabaci dapat menyebabkan kerusakan langsung dan tidak langsung pada cabai. Hama ini juga dikenal sebagai vektor virus untuk beberapa penyakit tanaman. Penanaman varietas tahan merupakan salah satu cara pengendalian kutukebul. Penelitian ini bertujuan untuk mempelajari kesesuaian inang kutukebul pada beberapa genotipe dan varietas cabai. Keenam genotipe dan varietas tersebut adalah Adelina, Anies, F10-074-2-1-B, IPB C12, Red Chupetinho, dan Red Habanero. Percobaan dilakukan dengan menggunakan no-choice test dengan tiga kali ulangan. Setiap genotipe dan varietas cabai ditanam di dalam kurungan dan diinfestasi lima imago betina. Pengamatan populasi kutukebul dilakukan setiap minggu selama lima minggu. Varietas Anies memiliki populasi kutukebul terendah, diikuti Red Habanero, Adelina, F10-074-2- 1-B, IPB C12, dan Red Chupetinho. Varietas Anies dan Red Habanero kurang sesuai untuk pengembangan kutukebul sehingga berpotensi untuk dikembangkan sebagai varietas cabai tahan B. tabaci., The Silverleaf whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), is one of the important pests of chili peppers. B. tabaci can cause direct and indirect damage to chili peppers. This pest is also known as a virus vector for several plant diseases. Planting resistant varieties is one of the methods to control the silverleaf whitefly. This study aimed to study the host suitability of silverleaf whitefly on several chili pepper genotypes and varieties. The six genotypes and varieties were Adelina, Anies, F10-074-2-1-B, IPB C12, Red Chupetinho, and Red Habanero. The experiment was done using a no-choice test with three replicates. Each chili pepper genotype and variety were planted in the cages and infested with five female adults. Observations on the silverleaf whitefly populations were done weekly for five weeks. The Anies variety had the lowest silverleaf whitefly populations, followed by Red Habanero, Adelina, F10-074-2-1- B, IPB C12, and Red Chupetinho, respectively. The Anies and Red Habanero varieties may not be suitable for developing the silverleaf whitefly, so they are potential to be developed as resistant chili varieties to B. tabaci.
Keyword: penyakit tanaman, tanaman inang, varietas tahan, vektor virus, host plant, plant disease, resistant variety, virus vector

Judul: Study of Chili Pepper Resistance to Aphis gossypii Based on Phenotypic, Metabolomic and Molecular
Abstrak: Produksi cabai di Indonesia terkendala oleh tingginya serangan hama penyakit. Kutudaun A. gossypii menyerang cabai di dataran rendah dan menjadi vektor berbagai jenis virus tanaman. Pengendalian kutudaun secara kimiawi sudah tidak efektif dikarenakan ketahanannya terhadap beberapa bahan aktif insektisida. Penggunaan varietas tahan kutudaun pada tanaman cabai diharapkan mampu meningkatkan kualitas dari produksi cabai, menurunkan transmisi virus, serta mengurangi beban penggunaan insektisida bagi petani dan lingkungan. Adapun tujuan dari penelitian ini adalah untuk mengkaji kendali genetik ketahanan cabai terhadap infestasi kutudaun A. gossypii dari aspek fenotipik, metabolomik, serta molekuler. Tahapan penelitian terdiri atas: 1) Pengembangan metode skrining cabai terhadap infestasi hama A. gossypii; 2) Evaluasi ketahanan cabai terhadap infestasi kutudaun pada populasi bersegregasi hasil persilangan genotipe tahan dan rentan; 3) Senyawa kimia (metabolit sekunder) cabai yang terkait dengan ketahanan terhadap infestasi kutudaun melalui teknik metabolomik pada populasi bersegregasi; serta 4) Pengembangkan marka molekuler yang dapat digunakan sebagai marker assisted selection (MAS) dalam proses pemuliaan tanaman cabai ketahananterhadap infestasi kutudaun A. gossypii. Hasil penelitian menunjukkan bahwa: 1) Semua metode skrining yang digunakan efektif dan metode uji clip cage terpilih sebagai metode pengujian yang handal dan praktis dalam uji ketahanan cabai terhadap infestasi A. gossypii; 2) Genotipe cabai IPB C367 dan IPB C20 memiliki ketahanan antibiosis terhadap kutudaun A. gossypii; 3) Ketahanan cabai dikendalikan secara resesif oleh banyak gen dengan aksi gen pengendali ketahanan hama kutudaun adalah aditif-epistasis duplikat; 4) senyawa 2,4-difluorobenzoic (fluorobenzoic acid) dan senyawa 2,5- octadecadiynoic acid (fatty acid) menjadi senyawa antibiosis tanaman cabai dalam menekan populasi koloni kutudaun A. gossypii.; dan 5) Terdapat tiga perubahan basa non-synonymous yang berpotensi untuk membedakan genotipe tahan dan genotipe rentan secara molekuler terhadap infestasi kutudaun A. gossypii. Belum adanya asosiasi yang kuat antara marka molekuler dengan fenotipe tanaman dalam mengidentifikasi gen ketahanan cabai terhadap kutudaun disebabkan oleh sifat ketahanan ini memiliki kompleksitas yang tinggi karena dikendalikan oleh banyak gen (poligen) secara resesif serta terdapat peran dari aksi gen epistasis duplikat., Chili pepper production in Indonesia is constrained by high pest attacks. The cotton aphid (CA), Aphis gossypii, attachesto chilies in the lowland and is a vector for various types of plant viruses. Chemical control of aphids is no longer effective due to their resistance to several insecticidal active ingredients. The use of aphid resistant varieties on chili peppers is expected to improve the quality of chili pepper production, reduce virus transmission, and reduce the cost of using insecticides for farmers and the environment. The purpose of this study was to examine the genetic control of chili pepper resistance to CA infestation from phenotypic, metabolomic, and molecular aspects. The stages of the research consisted of: 1) the development of a chili pepper screening method for CA infestation; 2) the evaluation of chili pepper resistance to aphids in segregated populations resulting from crosses of resistant with susceptible chili genotypes; 3) the identification of chemical compounds (secondary metabolites) of chili that are related to resistance to CA through metabolomic techniques in segregated populations; and 4) the development of moleculer markers that can be used as market assisted selection (MAS) in the chili pepper breeding program for resistance to CA.
Keyword: antibiosis, clip cage, heritabilitas, no choice test, pewarisan sifat

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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