Judul: Flower Induction of Marigold ‘Sudamala  Barak’ (Tagetes patula) with Plant Growth Regulator
Abstrak: Tagetes patula merupakan tanaman multifungsi, terutama pada bagian bunganya. Salah satu varietas dalam negeri yang potensial dikembangkan adalah Sudamala Barak, namun varietas ini memiliki umur berbunga yang lama yaitu 13-15 minggu sejak ditanam. Penelitian ini bertujuan mengetahui pengaruh ZPT (zat pengatur tumbuh) BAP (benzyl amino purine), GA3 (gibberellin acid), dan PBZ (paclobutrazol) terhadap respon pembungaan tanaman marigold ‘Sudamala Barak’ serta mengetahui konsentrasi terbaiknya. Penelitian dilaksanakan di dalam rumah kaca Kebun Percobaan Leuwikopo, IPB pada bulan September 2023 hingga Maret 2024. Penelitian ini menggunakan rancangan kelompok lengkap teracak dengan satu faktor yaitu jenis serta konsentrasi ZPT. Terdapat 10 taraf perlakuan yang terdiri dari kontrol (tanpa ZPT), BAP (50, 100, 150 ppm), GA3 (100, 200, 300 ppm), dan PBZ (50, 100, 150 ppm). Pengamatan meliputi karakter generatif dan vegetatif. Hasil penelitian menunjukkan pemberian ZPT berpengaruh nyata terhadap jumlah bunga, bobot total bunga, panjang tunas, panjang daun, dan panjang anak daun. Persentase tanaman berbunga tertinggi ditemukan pada perlakuan GA3 200 ppm (66,6%). Pengaruh ZPT terhadap karakter generatif menunjukkan GA3 200 ppm menghasilkan jumlah bunga dan bobot total bunga terbesar dibandingkan seluruh perlakuan lainnya. Hasil percobaan ini menunjukkan bahwa GA3 200 ppm berpotensi menginduksi pembungaan T. patula ‘Sudamala Barak’. Pada karakter vegetatif, pemberian BAP memberikan pengaruh yang netral kecuali pada BAP 150 ppm menghambat pemanjangan tunas, sementara GA3 mendorong pemanjangan tunas, dan PBZ menghambat pertumbuhan vegetatif., Tagetes patula is a multifunctional plant, especially in its flower parts. One potential domestic variety to be developed is Sudamala Barak, however this variety has a long juvenile period, which lasts for 13-15 weeks since planting. This study aimed to determine the effect of PGRs (plant growth regulation) BAP (benzyl amino purine), GA3 (gibberellic acid), and PBZ (paclobutrazol) on the flowering response of the marigold 'Sudamala Barak' and to determine the best concentrations. The research was conducted in the greenhouse of Leuwikopo Experimental Station, IPB University from September 2023 to March 2024. The experiment applied a completely randomized design with one factor, PGRs. There were 10 treatment levels consisting of control (without PGRs), BAP (50, 100, 150 ppm), GA3 (100, 200, 300 ppm), and PBZ (50, 100, 150 ppm). Observations included generative and vegetative characters. The results showed that the application of PGRs significantly affected the number of flowers, total flower weight, length of formed shoots, leaf length, and leaflet length. The highest percentage of plant flowering was found on GA3 200 ppm (66,6%). GA3 200 ppm treatment also produced the largest number of flowers and total flower weight compared to all other treatments. This experiment results imply that GA3 200 ppm has the potential inducer to induce flowering in T. patula ‘Sudamala Barak’. In the vegetative characteristics, the application of BAP had a neutral effect except at 150 ppm, where it inhibited shoot elongation, while GA3 promoted shoot elongation, and PBZ inhibited vegetative growth.
Keyword: benzyl amino purine, flower mechanism, gibberellic acid, paclobutrazol, production

Judul: Growth and Flower Yield of African Marigold (Tagetes erecta L.) under Different Pinching Frequencies and Fertilizer Types
Abstrak: Penelitian terkait pengaruh frekuensi pinching (setiap 2, 4 dan 6 hari) serta jenis pupuk (AB Mix dan NPK + Gandasil) terhadap pertumbuhan dan produksi marigold dilakukan di Kebun Percobaan CV. Benih Dramaga pada bulan Maret Juli 2023. Sebanyak tiga percobaan dilakukan secara terpisah berdasarkan bahan tanam, yaitu stek var. Sudamala Oranye 1 serta stek dan benih var. Maharani F1. Percobaan menggunakan stek dilakukan dengan Rancangan Kelompok Lengkap Teracak (RKLT) faktorial dua faktor yaitu frekuensi pinching serta jenis pupuk, benih dilakukan menggunakan RKLT dengan faktor jenis pupuk. Hasil penelitian menunjukkan bahwa frekuensi pinching berpengaruh nyata terhadap persentase tanaman berbunga, diameter serta bobot kuntum Sudamala Oranye 1. Jenis pupuk berpengaruh nyata terhadap persentase tanaman berbunga, warna daun dan mahkota bunga kedua varietas, persentase tanaman terserang layu bakteri Sudamala Oranye 1, serta jumlah tunas per minggu, total cabang baru, bobot segar bunga per tanaman, dan produktivitas Maharani F1 dari benih. Interaksi ditemukan pada jumlah tunas 5 dan 6 MST, total tunas baru per tanaman, dan diameter kuntum Sudamala Oranye 1. Pada kedua varietas, pinching 2 hari sekali menghasilkan komponen hasil tertinggi walaupun tidak berbeda nyata dengan frekuensi pinching lainnya. Sudamala Oranye 1 memiliki produksi tertinggi dengan pemberian AB Mix, sedangkan Maharani F1 pada aplikasi pupuk NPK + Gandasil., A research was conducted at CV. Benih Dramaga from March to July 2023 to study the effect of different pinching frequencies (every 2, 4 and 6 days) and fertilizer types (AB Mix and NPK + Gandasil) on marigold growth and flower yield. Three separate experiments were carried out based on planting material, namely cuttings of var. Sudamala Oranye 1, as well as cuttings and seeds of var. Maharani F1. The field experiments for cutting were carried out as factorial randomized block design (RCBD) with three replications in all possible combinations, while from seed used RCBD with seven replications and fertilizer types as the factor. The results revealed that pinching frequency significantly influenced the percentage of yielding plants, also diameter and fresh weight of individual flower of Sudamala Oranye 1. Fertilizer type significantly affected the percentage of yielding plants, leaf and flower petal color of both varieties, and the percentage of bacterial wilt-infected plants in Sudamala Oranye 1. Additionally, the number of shoots per week, total new shoots, fresh weight of flower per plant, and yield per hectare of Maharani F1 were significantly impacted. Interactions were observed in some growth parameters of Sudamala Oranye 1. In both varieties, pinching every 2 days produced the highest yield components, although not significantly different from other pinching frequencies. The highest Sudamala Oranye 1 flower yield was found with application of AB Mix, while NPK + Gandasil showed the highest yield in Maharani F1.
Keyword: AB Mix, Gandasil, Frekuensi pinching, NPK, Stek marigold, Pinching frequency, Shoot cuttings of marigold

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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