Judul: Interspecies protoplasts fusion between citrus siam simadu (Citrus nobilis Lour.) and citrus mandarin satsuma (C. unshiu Marc.)
Abstrak: Somatic hybridization is an important tool for supplying new varieties to be used directly as cultivar genetic improvement programs. In citrus, this technology has been extensively used and has many important implipications. The objectives to the research are produceed citrus somatic hybrids between citrus siam Simadu and Mandarin Satsuma with chemical fusion (PEG). Protoplasts of siam Simadu from calli with Mandarin Satsuma from mesophyll-derived protoplasts were regenerated by somatic embryogenesis. Concentration and duration of incubation in a solution of PEG strongly affected the fusion induction of siam Simadu with Mandarin Satsuma. High concentrations of PEG can increase the frequency of fusion, while the low concentration produces a low frequency of fusion. The result showed that protoplasts from embryogenic callus of Simadu tangerine and in vitro leaf of Mandarin Satsuma can be isolated in large numbers by using a combination of cellulase Onozuka R10, Yakult Yakult% 1% with R10 Maserozim in CPW solution. Protoplasts are purified with a mixture of 25% sucrose with 13% mannitol. Protoplast density produced from embryogenic callus is 15.7x105 protoplasts / g callus and 13x105 protoplasts/ g in vitro leaf. The concentration of PEG used to induce fusion between mesophyll protoplasts Mandarin Satsuma and siam Simadu callus affect the average number of protoplasts fusion. Average number of protoplasts were fused by using PEG 4% are 3.3 hetero fusion, 5.0 homo fusion and multi-fusion. Average number of protoplasts were fused by using PEG 30% are 4.7 hetero fusion, 6.7 homo fusion 6.7 and 7.7multi-fusion. The success of fusan regeneration on regeneration medium is influenced by PEG concentration used for induction of fusion. Protoplasts were fused with PEG only 4%, which can regenerate to form cell walls, making cell division, colony cells, micro-callus and somatic embryo. Protoplasts were fused with PEG 30% can only be regenerated to form the cell wall and cell division. Giving light to the culture after 2 weeks may accelerate cell division that can form colonies of cells. Dilutions of cell suspension with the same medium (without 2, 4-D) can accelerate the growth and development of the protoplasts formed colonies of cells, micro-callus and somatic embryos. MW medium is best used in the fusion because it can encourage of somatic embryos directly. Addition of ABA 0.5 mg / l in the media can produce somatic embryos and GA3 0.5 mg / l can germinate mature somatic embryos to plantlets with 76% germination efficiency. Somatic hybrids were germinated, then trasfered to a medium culture, and finally grafted in greenhouse. The hybrids were confirmed by growth of in vitro culture, morphology, cytology (chromosome number), molecular analysis (ISSR), and contain of chlorophyl Keywords: Citrus, male sterility, chemical fusion, somatic embryogenesis, morphology,
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Judul: Flowering biology and parthenocarpy of citrus derived from somatic hybridization of Mandarin Satsuma (Citrus unshiu Marc.) and Siam Madu (Citrus nobilis Lour.)
Abstrak: Fusi protoplas antara Mandarin Satsuma (Citrus unshiu Marc.) dan Siam Madu (Citrus nobilis Lour.) diharapkan menghasilkan buah dengan rasa yang enak dan mempunyai biji sedikit, namun kenyataannya menghasilkan hibrida dengan variasi genetik yang tinggi. Tujuan penelitian ini adalah mendapatkan informasi biologi pembungaan dan pembentukan buah serta sifat partenokarpi jeruk hasil fusi protoplas antara Mandarin Satsuma dan Siam Madu. Penelitian dilaksanakan di KP Pacet BB Biogen, Cianjur (1150 m dpl), selama Agustus 2019 – Juli 2020. Bahan penelitian berupa 15 galur jeruk hasil fusi protoplas (Mandarin Satsuma dan Siam Madu), masing-masing terdiri atas 5 tanaman (umur ± 2 tahun), yang diperbanyak secara okulasi dengan batang bawah JC (okulasi pada bulan Juni 2017). Biologi pembungaan diamati secara deskriptif mencakup morfologi bunga, perkembangan bunga dan buah, viabilitas serbuk sari dan reseptivitas stigma. Pembentukan buah dan biji dari bunga tanpa penyerbukan, penyerbukan sendiri dan silang untuk mendapatkan informasi adanya sifat partenokarpi pada tanaman hasil fusi protoplas. Hasil pengamatan menunjukkan bahwa morfologi bunga galur-galur tanaman jeruk hasil fusi protoplas cukup beragam dan mewarisi karakter kedua tetuanya. Fase pembentukan bunga hingga buah masak bervariasi antar galur, dengan lama perkembangan yang berkisar 212 – 316 hari. Media yang tepat untuk pengecambahan serbuk sari menggunakan media PGMm. Viabilitas serbuk sari tertinggi dan masa reseptif stigma tercapai pada saat bunga mekar sempurna. Galur FS 25 menghasilkan serbuk sari dengan viabilitas yang paling rendah dan buah tidak terbentuk tanpa penyerbukan. Penyerbukan sendiri FS 25 dan penyerbukan silang dengan FS 84 dan FS 89 menghasilkan persentase buah tanpa biji tertinggi. Penyerbukan antar galur yang cross-compatible diperlukan untuk produksi buah tanpa biji pada galur dengan potensi partenokarpi stimulatif yang kuat. FS 25 memiliki karakter partenokarpi stimulatif, dan FS 84 dan FS 89 dapat digunakan sebagai sumber serbuk sari untuk menstimulasi pembentukan buah tanpa biji., The somatic hybridization between Mandarin Satsuma (Citrus unshiu Marc.) and Siam Madu (Citrus nobilis Lour.) is expected to produce seedless fruit with good taste, but in fact produces hybrids with high genetic diversity. The purpose of this study was to obtain information on flowering biology and fruit formation as well as the parthenocarpic characters of the genotypes from somatic hybridization between Mandarin Satsuma and Siam Madu. The research was carried out at Pacet Experimental Station, BB Biogen, Cianjur (1150 m asl), during August 2019-July 2020. The research materials were 15 citrus lines resulting from somatic hybridization (Mandarin Satsuma and Siam Madu), each consisting of 5 plants (± 2 years old), which were propagated by grafting with JC rootstocks (grafting at June 2017). Flowering biology was observed descriptively including flower morphology, flower and fruit development, pollen viability and stigma receptivity. Development of fruit and seeds from flowers without pollination, self-pollination and cross-pollination were observed to invertigate the existence of parthenocarpy in plants resulting from somatic hybridization. The result showed that the flower morphology of citrus somatic hybridization lines varied and inherits the characters of both parents. The development from flower bud until fruit ripening varied among lines, ranged 212-316 days. The modified PGM was the most suitable for citrus pollen germination. The pollen viability was the highest at blooming during which
Keyword: BBCH, numbers of petal, stimulative parthenocarpy, self-pollinated, pollen viability

Judul: Fenomena Arus Rabak (Rip Current) Di Kawasan Pantai Panjang, Kota Bengkulu
Abstrak: Tingginya kunjungan wisatawan namun minim pengetahuan tentang kondisi pantai, dapat menyebabkan adanya risiko kecelakaan pantai yang tinggi. Arus rabak adalah salah satu penyebab terjadinya kecelakaan pantai. Tercatat sebanyak 35 kasus terseretnya wisatawan pernah terjadi di Pantai Panjang dari tahun 2009 hingga tahun 2021. Penelitian ini bertujuan menggambarkan kondisi oseanografi pada lokasi yang berpotensi munculnya arus rabak berdasarkan musim, jenis arus rabak, serta menjelaskan karakteristik arus rabak melalui ciri dan proses pembentuk arus rabak. Lokasi penelitian dilakukan di Pantai Panjang, Kota Bengkulu. Analisis arus rabak menggunakan model SWAN, kedalalaman perairan, angin dan citra satelit. Topografi dasar laut pesisir Bengkulu relatif landai. Gelombang signifikan tertinggi terjadi pada bulan Januari 2017 yaitu 0.25 m dengan periode gelombang terlama terjadi pada bulan April 2021 yaitu 1.63 s. Karakteristik tipe gelombang pecah Pantai Panjang yaitu plunging. Fenomena arus rabak kerap terjadi di Pantai Panjang dengan jenis bar-gap rips. Pembentukan arus rabak dipengaruhi oleh kondisi topografi. Arus rabak yang terjadi di Pantai Panjang dapat ditemui s
Keyword: Arus rabak, Gelombang, Pantai Panjang, SWAN, Topografi, Panjang Beach, Rip Current, Topography, Wave