Judul: Potensi Hutan Rakyat Mindi (Melia azedarach L.) Sebagai Sumber Benih: Variabilitas Genetik Pohon Induk, Morfologi Benih dan Pertumbuhan Bibit
Abstrak: Mindi (Melia azedarach L.) merupakan salah satu jenis yang umum ditemukan di hutan rakyat Jawa Barat. Salah satu faktor yang yang mempengaruhi produktivitas hutan rakyat adalah benih yang berkualitas. Akan tetapi, informasi tentang kualitas sumber benih di hutan rakyat saat ini masih kurang, baik mutu fisik, genetik, maupun fisiologi. Tujuan dari penelitian ini adalah untuk: 1) menduga keragaman genetik di dalam dan antar populasi mindi di hutan rakyat Jawa Barat, dan 2) menduga variabilitas dimensi buah mindi yang dikumpulkan dari lima sumber benih yang berbeda, dan pertumbuhan bibit mindi di persemaian pada tujuh media yang berbeda dari campuran top soil, pasir, arang sekam, dan pupuk kandang berupa kotoran sapi. Hasil penelitian menunjukkan rata-rata alel yang teramati (Ne) sebesar 2.200, PLP (percentage of polymorphic loci) sebesar 93.33%, dan keragaman genetik dalam populasi (He) mindi sebesar 0.366. Keragaman genetik tertinggi adalah populasi Padasari (He= 0.454) dan terendah adalah Babakan Rema (He= 0.220). Rata-rata nilai perbedaan genetik antar populasi (Fst) didapatkan 0.303. Pada analisis klaster menunjukkan adanya pengelompokan populasi mindi yang terbagi menjadi 3 klaster. Klaster pertama terdiri atas Nagrak dan Padasari, klaster ke dua Babakan Rema, Gambung dan Sukakarya, serta klaster ke tiga hanya populasi Legok Huni. Klaster yang sama menunjukkan kekerabatan yang dekat. Berdasarkan hasil penelitian, keragaman genetik populasi mindi tergolong pada keragaman sedang, yang dapat dijadikan pertimbangan pada waktu seleksi dan pembangunan sumber benih. Variabilitas dimensi buah mindi secara spasial yang dikumpulkan dari lima sumber benih berbeda, dan pertumbuhan bibit mindi di persemaian tergolong sedang. Buah mindi dari Nagrak mempunyai ukuran, berat, dan seed set yang paling tinggi, serta persentase, nilai dan kecepatan kecambah paling tinggi. Hasil pengamatan pertumbuhan bibit mindi dari sumber benih dan media sapih berbeda menunjukkan bahwa bibit dari Nagrak memiliki pertumbuhan lebih cepat. Media sapih yang mengandung pupuk kandang berupa kotoran sapi memberikan pertumbuhan paling cepat.
Keyword: hutan rakyat, mindi, sumber benih, pertumbuhan bibit, media sapih

Judul: Strategi pengembangan sumber benih mindi (Melia azedarach L.) pada hutan rakyat di Provinsi Jawa Barat
Abstrak: Melia azedarach L. or mindi (local name) is one of the widely planted exotic species in Indonesia, mostly found in community forests in West Java. It is still an urgent need for improvement of mindi plantation productivity, especially in community forest in West Java. One of the factors that affect forest productivity is high quality seed, but seed quality is not easily obtained by farmers. For this it is necessary to carry out a strategies which can support the development of seed sources in the community forest. The general objective of this research is to formulate development strategies of mindi seed sources in the community forest in West Java, while specific purposes of this study are to (1) determine the genetic and morphology diversity of mindi in the community forest in West Java, (2) improve seed pre-treatment to develop the seed viability of mindi, and (3) analyze of socio-economic and institutional aspect of farmers, to support the development of the seed sources. Six populations of mindi plantation in the community forests were chosen for this research. i.e Nagrak village (Bogor); Megamendung (Bogor); Hamlet of Gambung (Bandung); Wanayasa subdistrict (Purwakarta); Padasari village (Sumedang) and Babakan Rema village (Kuningan). RAPD markers were used to assess the genetic variation, while various pre-treatments employing chemical and physical methods were tested to improve seed viability and vigor. SWOT analysis was used to evaluate the capacity of farmers in developing seed source. The results showed that the genetic variation of mindi in community forests in West Java was moderate ranging from He = 0.1603-0.1956. With respect to seed treatment, the use of sulfuric acid (95%) increased the viability of seed by 57% over control, especially seed from Padasari (Sumedang) population. Prospective populations to be developed for seed sources were proposed namely Padasari (Sumedang) and Legok Huni (Purwakarta). Evaluation of socio-economic and institutional aspect in these two location showed that generally farmers have the sufficient capacity to manage community forests. Four strategies that can be used to develop seed sources of mindi in community forest in West Java : i.e 1. The strategy based on utilization of plant genetic resources of mindi to increase seed production in order to meet the need of mindi timber market. 2. The strategy based on market and networking opportunities to improve the quality of mindi seeds . 3. The strategy based on capacity building and institutional development of farmers in the cultivation of mindi. 4. The strategy based on increasing farmers' interest in cultivation of mindi In conclusion, effective strategy of mindi seed source development should emphasize following important considerations such as the utilization of exisiting genetic resources, enhancement of institutions and networks as well as optimizing opportunities in mindi timber markets.
Keyword: Benih Mindi, Melia azedarach L., Hutan Rakyat, Jawa Barat

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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