Judul: Seed Characterization of Foxtail Millet  (Setaria italica L. Beauv.) ICERI and Botok Genotypes Using Digital Imaging  Technology
Abstrak: Karakterisasi biji berukuran kecil secara manual, seperti biji hotong, membutuhkan ketelitian yang tinggi, cenderung subjektif, dan membutuhkan waktu yang relatif lama. Oleh karena itu, perlu dikembangkan suatu metode yang efisien dan akurat untuk mengkarakterisasi biji hotong, salah satunya dengan memanfaatkan teknologi citra digital (digital imaging). Analisis citra digital dengan ImageJ dapat memperoleh data kuantitatif untuk morfologi bentuk biji seperti jumlah, ukuran, perimeter, width, height, circularity, aspect ratio, round, dan solidity. Penelitian ini bertujuan untuk mengembangkan model pendugaan bobot 100 biji genotipe hotong yang berasal dari Indonesia menggunakan perangkat lunak pencitraan digital ImageJ v1.53. Penelitian ini dilaksanakan pada bulan November 2021 hingga Februari 2022 di Laboratorium Biologi dan Biofisika Benih, Departemen Agronomi dan Hortikultura, Institut Pertanian Bogor, Dramaga, Bogor. Penelitian ini terdiri atas dua tahap percobaan. Percobaan pertama menggunakan 14 genotipe hotong Indonesia dari ICERI dan Botok untuk mengembangkan model pendugaan karakter jumlah biji dan bobot 100 biji. Model y = 329,17x2 - 2,3606x + 0,0774 (R²= 0,948) menunjukkan korelasi positif dan sangat nyata (r=0,974, p<0.01) antara prediksi bobot 100 butir menggunakan ImageJ dengan bobot 100 butir aktual. Model tersebut kemudian divalidasi pada percobaan kedua yang menggunakan biji dari 30 galur F3 hasil persilangan Botok-4xICERI-6. Hasil validasi menunjukkan korelasi positif dan sangat nyata (r=0,606, p<0.01) antara nilai prediksi bobot 100 butir dan nilai aktualnya, Manual characterization of small size seeds, such as seed of foxtail millet, requires high accuracy, tends to be subjective, and requires a relatively long time. Therefore, it is necessary to develop an efficient and accurate method to characterize foxtail millet seeds, one of which is by utilizing digital image technology (digital imaging). Digital image analysis with ImageJ can obtain quantitative data for seed morphology such as number, size, perimeter, width, height, circularity, aspect ratio, round, and solidity. The objective of this study was to develop a model for estimating 100 seed weight of Indonesian foxtail millet genotypes utilizing digital imaging software ImageJ v1.53. This research was conducted from November 2021 to February 2022 at Seed Biology and Biophysics Laboratory, Department of Agronomy and Horticulture, IPB University, Dramaga, Bogor. This research consisted of two steps of experiments. The first experiment utilized 14 Indonesian foxtail millet from genotypes of ICERI and Botok to develop a model for estimating 100 seed weight. A model of y = 329.17x2 – 2.3606x + 0.0774 (R²= 0.948) showed a positive and highly significant correlation (r=0.974, p<0.01) between predicted 100 seed weight using ImageJ with the actual 100 seed weight. The model was then validated in the second experiment that utilized seeds from 30 F2 plants from Botok-4xICERI-6 crossing. The validation results showed a positive and highly significant correlation (r=0.606, p<0.01) between the predicted and actual values of 100 seed weight.
Keyword: bobot 100 biji, jumlah biji, ImageJ, korelasi, model estimasi

Judul: Characterization and Evaluation of Eight Foxtail Millet Genotypes (Setaria italica L. Beauv) from Exploration
Abstrak: Hotong (Setaria italica L. Beauv) ialah sumber karbohidrat yang mampu beradaptasi baik di lingkungan kering dan kurang subur. Tanaman ini memiliki kandungan protein, kalsium, dan antioksidan yang cukup tinggi dibandingkan padi dan jagung. Pemanfaatan hotong sebagai sumber pangan di Indonesia masih terbatas karena belum adanya varietas unggul hotong yang dilepas. Penelitian ini bertujuan mengetahui karakter agronomi dan karakter morfologi dari empat genotipe hotong hasil eksplorasi dan empat genotipe pembandingnya. Percobaan dilaksanakan pada bulan Februari - September 2021 di Kebun Percobaan Cikabayan Bawah IPB. Penelitian ini terdiri atas tiga percobaan, setiap percobaan disusun berdasarkan rancangan kelompok lengkap teracak (RKLT) faktor tunggal dengan delapan ulangan. Bahan penelitian yang digunakan terdiri atas empat genotipe hasil eksplorasi yaitu Hambapraing, Mauliru#2, Toraja, dan NTB-1, dan empat genotipe pembanding yaitu ICERI-5, ICERI-6, Botok-4, dan Botok-10. Berdasarkan scatter plot dan dendrogram yang dibangun, delapan genotipe yang diamati terbagi menjadi dua kelompok besar. Kelompok A terdiri dari genotipe ICERI-5, ICERI-6, dan Toraja dengan produktivitas yang rendah dan umur panen yang singkat. Kelompok B terdiri dari genotipe Mauliru#2, Hambapraing, NTB-1, Botok-4, dan Botok-10 dengan produktivitas yang tinggi dan umur panen yang cukup lama., Foxtail millet (Setaria italica L. Beauv) is a source of carbohydrates that adapt well in dry and less fertile environments. Foxtail millet contains higher protein, calcium, and antioxidants compared to rice and corn. The utilization of foxtail millet in Indonesia as food is still limited and there is no superior variety of foxtail millet has been released in the country. The objective of this study was to characterize foxtail millet genotypes collected from exploration. The study was conducted from February - September 2021 at the Cikabayan Experimental Field, IPB University. The study consisted of three experiments, each experiment was arranged in a randomized complete block design (RCBD) with eight replications. Foxtail millet genotypes used in this study were four genotypes collected from exploration activity namely Hambapraing, Mauliru#2, Toraja, and NTB-1, and four check genotypes namely ICERI-5, ICERI-6, Botok-4, and Botok-10. Based on the constructed scatter plot and dendrogram, the eight observed genotypes were divided into two large groups. Group A consists of the genotypes ICERI-5, ICERI6, and Toraja with low productivity and early maturity. Group B consists of genotypes Mauliru #2, Hambapraing, NTB-1, Botok-4, and Botok-10 with high productivity and late maturity.
Keyword: cereals, characterization, diversity, exploration, productivity

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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