Judul: Kendali Genetik Sifat Ketahanan Melon (Cucumis melo. L.) Terhadap Penyakit Virus Kuning
Abstrak: Resistance to yellow virus (YV) is an important breeding character in melon. However there is limited information regarding the genetic inheritance of the character. This study aimed at providing information on genetic control for resistance to YV in melon. The research consists of three field experiments, there were evaluation of resistance to YV and parent selection, evaluation of resistance in P1, P2, F1 and F2 population, and agronomic character evaluation. The research was conducted in July 2011 - September 2012. Twenty genotypes from three major melon groups were evaluated and one line from the dudaim group (MEV1) was high resistance to YV, other lines belong to cantaloupe and inodorous showed highly susceptible performance. Resistance screening of F1 from resistance x susceptible parent showed resistance among the F1. Resistance evaluation in F2 population showed disease severity score was not in normal distribution. It means that resistance to YV was controlled by major genes. Chi square test result gave 13:3 as a suitable ratio, which the resistance to YV was controlled by two gene pair with dominant and epistasis recessive action. Nineteen genotypes were grouped into four major groups by clustering analysis with 25 variable in 85% similarity level. Group I consist of seven genotypes, MEV2, MEV3, MEV4, MEV5, MEV6, MEV7 and MEV8 (susceptible parent from cantaloupe group). Group II consist of two genotypes, MEV18 and MEV19 that belong to susceptible parent from inodorous group. Group III consist of seven genotypes, MEV2X1, MEV3X1, MEV4X1, MEV5X1, MEV6X1, MEV7X1 and MEV8X1 as a resistance F1 (cantaloupe x dudaim). Group IV consist of three genotypes, MEV18X1, MEV19X1 as a F1 ( inodorous x dudaim) and MEV1 that belong to resistance parent from dudaim group. Path analysis showed that strong leaf blade dentation gave highest negative direct effect toward virus intensity, with -0.529 as a coefficient value. It mean that leaf blade character linked with resistance to YV. Selection to plant which weak leaf blade dentation will be more enable to obtain plant which resistance to YV.
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Judul: Tingkat ketahanan sembilan galur cucumis melo L. terhadap squash mosaic comovirus
Abstrak: Cucumis melo L. merupakan salah satu spesies tanaman dalam famili Cucurbitaceae, diantaranya yaitu melon dan blewah. Melon lebih disukai masyarakat untuk dikonsumsi langsung sebagai buah segar, sedangkan blewah karena kualitas kemanisannya yang lebih rendah daripada melon, sehingga lebih sering dimanfaatkan sebagai campuran es buah dan sirup. SqMV sebagai salah satu gangguan dalam upaya pengembangan C. melo dapat mengurangi nilai ekonomi komoditas tersebut. Penggunaan varietas tahan untuk pengendalian virus sangat penting, tetapi sampai saat ini belum ada laporan tentang varietas-varietas C. melo yang tahan terhadap SqMV. Tujuan penelitian ini adalah mengetahui keragaman ketahanan dari sembilan galur C. melo terhadap SqMV dan mengetahui adanya galur yang resisten terhadap SqMV. SqMV diperbanyak pada tanaman kaboca. Setiap galur diinokulasi dengan SqMV secara mekanis. Sebagai kontrol, masing-masing galur C. melo juga diinokulasi dengan bufer fosfat. Percobaan ini dilakukan dalam rancangan acak kelompok (RAK) dengan dua faktor pembeda yaitu galur dan inokulasi dengan SqMV dan tanpa SqMV. Tiap perlakuan terdiri dari 6 ulangan, 1 ulangan terdiri dari 1 tanaman. Pengamatan dilakukan terhadap masa inkubasi, kejadian penyakit, tipe gejala, pertambahan tinggi tanaman, masa berbunga, jumlah bunga hermafrodit yang mekar, bobot buah. tingkat kemanisan buah, bobot basah dan bobot kering tanaman. Secara umum 9 galur tanaman C. melo ini menunjukkan tingkat ketahanan yang beragam terhadap infeksi SqMV. Respon agak rentan ditunjukkan oien galur hasil persilangan melor. Honey Dew x melon Action 434. Berdasarkan hasil penelitian diketahui bahwa galur hasil selfing varietas melon menunjukkan tingkat ketahanan yang sama dengan galur hasil selfing varietas blewah yaitu rentan, kecuali pada galur hasil selfing blewah Bisma yang menunjukkan respon sangat rentan terhadap infeksi SqMV. Galur hasil persilangan antara varietas melon menunjukkan tingkat ketahanan yang lebih baik dibandingkan dengan galur hasil persilangan antara varietas blewah.
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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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