Judul: Digital Imaging for Seed Characterization of Indonesian  Foxtail Millet (Setaria italica (L.) Beauv) Local Genotypes
Abstrak: Karakterisasi biji termasuk ukuran, jumlah, dan bobot biji merupakan karakter penting dalam proses seleksi genotipe. Karakterisasi biji secara manual pada tanaman berbiji kecil seperti hotong (Setaria italica (L.) Beauv) tidak mudah untuk dilakukan. Karakterisasi biji secara manual rentan terhadap kesalahan dan memerlukan waktu cukup lama. Penggunaan teknologi citra digital diharapkkan dapat mempercepat, memudahkan, dan meningkatkan akurasi karakterisasi biji hotong. Tujuan penelitian ini adalah pemanfaatan perangkat lunak citra digital ImageJ v1.53 untuk melakukan karakterisasi biji hotong dan mengembangkan model estimasi bobot 100 butir biji menggunakan biji hotong genotipe lokal Indonesia. Penelitian ini dilaksanakan pada bulan November 2021 hingga Febuari 2022 di Laboratorium Biologi dan Biofisik Benih, Departemen Agronomi dan Hortikultura, IPB, Dramaga, Bogor. Penelitian terdiri atas dua tahap percobaan. Percobaan pertama menggunakan 14 genotipe hotong lokal Indonesia untuk melakukan karakterisasi morfologi biji hotong dan membuat model pendugaan untuk bobot 100 butir biji. Model tersebut lalu divalidasi pada percobaan kedua yang menggunakan biji dari 30 famili F3 hasil persilangan ICERI-6xBotok-4. Model pendugaan yang didapatkan yaitu 11,748x - 0,0772 (R2=0,811) menunjukan korelasi positif dan sangat nyata (r=0,901, p<0,01) pada saat bobot prediksi 100 butir biji menggunakan ImageJ dan bobot 100 butir biji aktual dibandingkan. Model pendugaan kemudian divalidasi pada percobaan kedua dan juga menghasilkan korelasi positif dan sangat nyata (r=0,825, p<0,01). Selain mengestimasi jumlah biji, perangkat lunak ImageJ dapat mengestimasi beberapa karakter biji lainnya yaitu perimeter, width, height, circularity, aspect ratio, round, dan solidity., Seed characters, including seed size, seed number and seed weight, are important characters in genotypes selection. Manual characterization of seeds in plants with small seed size, such as in foxtail millet (Setaria italica (L.) Beauv) is challenging, prone to errors, and needs plenty of time. Utilization of digital imaging technology is expected to provide faster, easier and more accurate seed characterization in foxtail millet. The objective of this study was to obtain morphological seed characters and utilize ImageJ v1.53. digital imaging software to develop model in estimating 100 seed weight using Indonesian foxtail millet local genotypes. This research was conducted from November 2021 to February 2022 at Seed Biology and Biophysics Laboratory, Agronomy and Horticulture Department, IPB University, Dramaga, Bogor. This research consisted of two steps of experiments. The first experiments utilized 14 Indonesian foxtail millet local genotypes to obtain morphological seed characters and develop the model in estimating 100 seed weight character. The model was then validated in the second experiment that utilized seeds from 30 F3 lines from ICERI-6xBotok-4 crossing. A model of 11.748x – 0.0772 (R2=0.811) showed high a positive and highly significant correlation (r=0.901, p<0.01) between predicted 100 grain weight using ImageJ with the actual 100 grain weight. The model was then validated in second experiment and shown high a positive and highly significant correlation (r=0.825, p<0.01). The ImageJ software could also identify other seed characters including perimeter, width, height, circularity, aspect ratio, round, and solidity.
Keyword: 100 grains weight, Estimation model, ImageJ, Seed area, Seed shape

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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