Judul: Identification of Target-site Resistance to Glyphosate on Eleusine indica (L.) Gaertn. from Jonggol Oil Palm Plantation, Bogor, West Java
Abstrak: Resistensi glifosat dapat terjadi melalui mekanisme target-site resistance (TSR) dengan adanya mutasi pada gen target herbisida yaitu 5-enolpiruvil-sikimat-3-fosfat sintase (EPSPS). Penelitian ini bertujuan mengidentifikasi mekanisme TSR yang berkaitan dengan TIPS mutation pada spesies Eleusine indica yang telah dilaporkan resisten di kebun kelapa sawit asal Jonggol, Bogor, Jawa Barat. Analisis bio-assay dilakukan menggunakan Rancangan Kelompok Lengkap Teracak (RKLT) faktor tunggal yaitu dosis herbisida dengan 8 taraf dosis dan 3 ulangan. Banyaknya satuan percobaan adalah 24 satuan percobaan setiap blok. Percobaan dimulai dengan pengambilan biji E. indica resisten pada Blok II dan Blok V. Biji gulma E. indica ditanam pada pot dengan cara disebar. Gulma yang telah tumbuh dipelihara dengan melakukan penyiangan, penyiraman, dan seleksi pertumbuhan agar seragam. Aplikasi glifosat dilakukan saat gulma berdaun 4 menggunakan delapan taraf dosis yaitu 0, 1/8x, 1/4x, 1/2x, x, 2x, 4x, 8x dengan x adalah dosis rekomendasi, sehingga dosis herbisida glifosat adalah 0, 121,5, 243, 486, 972, 1944, 3888, dan 7776 g ha-1. Volume semprot yang digunakan adalah 400 L ha-1. Persentase kerusakan gulma diperoleh dari biomasa tanaman kemudian analisis regresi dilakukan untuk memperoleh LD50 dan nisbah resistensi. Biotipe E. indica asal Kebun Jonggol Blok V memiliki LD50 sebesar 1737 g ha-1 dengan status resistensi penurunan sensitivitas dan nisbah resistensi 2,343. Blok II masih berstatus sensitif dengan nisbah resistensi 1,588 dan nilai LD50 sebesar 1177,30 g ha-1. Identifikasi TSR dilakukan dengan isolasi dan amplifikasi gen penyandi EPSPS dari DNA genom E. indica asal kebun kelapa sawit Jonggol sebagai biotipe resisten dan asal pinggir jalan kampus IPB Dramaga sebagai biotipe sensitif. Hasil runutan basa nukleotida disejajarkan menggunakan algoritma MUSCLE dan visualisasi hasil penjajaran menggunakan Geneious Prime. Hasil pensejajaran basa nukleotida menunjukkan tidak adanya titik mutasi penyebab resistensi glifosat pada rentang basa 979 sampai dengan 1280 gen penyandi EPSPS. Nilai LD50 yang tinggi pada pada Blok V mengindikasikan adanya potensi resistensi akibat perbedaan basa nukleotida pada titik lain dari gen EPSPS maupun mekanisme non-target-site resistance (NTSR)., Target-site resistance (TSR) to glyphosate is caused by mutation in targeted gene namely 5-enolpyruvyl-shikimate-3-phosphate synthase (EPSPS). This research was aimed to identify TSR mechanism assosiated with TIPS mutation in Eleusine indica biotypes from Oil Palm Plantation in Jonggol which was reported resistant recently. Bio-assay analysis was conducted using a single-factor Randomized Completely Block Design (RCBD), namely herbicide dose with 8 dose levels and 3 replications. The number of experimental units was 24 experimental units per block. The experiment began with the collection of resistant E. indica seeds in Block II and Block V. E. indica seeds were planted in pots by spreading. Weeds that had grown were maintained by weeding, watering, and selecting for uniform growth. Glyphosate application was carried out when the weeds were 4-leafed using eight dose levels, namely 0, 1/8x, 1/4x, 1/2x, x, 2x, 4x, 8x with x being the recommended dose, so that the herbicide dose of glyphosate was 0, 121.5, 243, 486, 972, 1944, 3888, and 7776 g ha-1. The spray volume used was 400 L ha-1. Percentage of weed damage was obtained from plant biomass then regression analysis was conducted to obtain LD50 and resistance ratio. E. indica
Keyword: bio-assay, EPSPS, LD50, resistance index, sequencing

Judul: Dominance of Weeds and The Potential of Resistance to Glyphosate Herbicides in Guava Plantation
Abstrak: Gulma pada pertanaman jambu kristal harus dikendalikan untuk mengurangi kompetisi. Pengendalian gulma menggunakan herbisida berbahan aktif yang sama secara terus menerus dapat menyebabkan gulma menjadi resisten terhadap herbisida. Pengujian resistensi gulma bertujuan melihat status gulma dominan yang berada pada pertanaman jambu kristal sehingga strategi pengendalian dapat dilakukan. Identifikasi gulma dominan menggunakan analisis vegetasi pada 4 blok menggunakan metode kuadrat. Setiap blok diambil 5 titik contoh dengan kuadran. Gulma dominan ditentukan berdasarkan Nisbah Jumlah Dominansi (NJD). Biji gulma dominan pada percobaan pertama diambil dari kebun ATP secara acak pada tiap blok sebanyak 20 titik yang kemudian ditanam sebanyak 25 bibit ke polybag setelah disemai. Gulma disemprot dengan herbisida dengan 9 taraf dosis yaitu kontrol 0 g.ha-1(D0), 60,75 g.ha-1(D1), 121,5 g.ha-1(D2), 243 g.ha-1(D3), 486 g.ha-1(D4), 972 g.ha-1(D5), 1.944 g.ha-1(D6), 3.888 g.ha-1(D7), dan 7.776 g.ha-1(D8) sebanyak 3 ulangan. Gulma kemudian dipanen dan dihitung % kematiannya. Hasil penelitian menunjukan bahwa gulma dominan di kebun ATP adalah Cyperus kyllingia. Tiap blok kebun jambu kristal memiliki nisbah resistensi yang berbeda dengan blok 4 yang tertinggi yaitu sebesar 2,129 (resistensi rendah)., Weeds in guava plantation must be controlled to reduce competition. Weed control using the same active ingredient herbicide continuously can cause weeds resistant. Weed resistance testing aimed to see the status of dominant weeds in guava plantations so that weed control strategies can be carried out. Dominant weeds identification used vegetation analysis in 4 blocks using the quadrant method. Each block was taken 5 sample points with a quadrant. Dominant weeds was determined based on the Sum Dominancy Ratio (SDR). The dominant weed seeds in the first experiment were taken from the ATP IPB field by taking ramdomly 20 points from each blocks, which were then planted as many as 25 seedlings into polybags after sowing. Weeds were sprayed with the glyphosate herbicide with 9 dose levels, namely control 0 g.ha-1(D0), 60.75 g.ha-1(D1), 121.5 g.ha-1(D2), 243 g.ha-1(D3), 486 g.ha-1(D4), 972 g.ha-1(D5), 1,944 g.ha-1(D6), 3,888 g.ha-1(D7), and 7.776 g.ha-1 (D8) with 3 replications. Weeds were then harvested and the %mortality was calculated. The results showed that the dominant weed in ATP field was Cyperus kyllingia. Each block had a different resistance ratio to glyphosate. Block 4 had the highest resistance ratio, which was 2.129 (low resistance).
Keyword: analisis vegetasi, dosis, ESPS, LD50

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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