Judul: Haploidization through androgenesis and gynogenesis on carnation (Dianthus sp.).
Abstrak: Haploidization technology ensures important advantages in obtaining pure lines by rapid fixation of homozygosity. Anther culture, ovule culture, ovary culture and irradiated pollen technique were used in this study. The objective of the research was to develop appropriate haploid technology in order to obtain haploid plants through androgenesis, gynogenesis by ovule culture and ovary culture and pseudofertilization on Dianthus chienesis. Androgenic callus was induced in four WT basic medium inductions supplemented with 2.4D, NAA, TDZ and BA. Four explants originated from ovule and ovary cultures of six genotypes of D. chinensis (Dchi-11, Dchi-12, Dchi-13, Dchi-14, Dchi-15 and Dchi-16) were applied in five media. For the parthenogenesis induction, 100-200 Gray gamma irradiations were applied to the Dchi-14 pollens and pollinated to the Dchi-11. Pollinations were conducted on the day after irradiation. Eight media were selected to obtain regenerated plants. Results showed that androgenic callus formation needed high auxin and sitokinin ratio, while regenerated callus required lower auxin and sitokinin ratio. 2,4-D was better than NAA in callus induction. Callus originated from anther culture, multi ovule slice culture, ovule culture and ovary slice culture regenerated producing early flowering plants and expressed of abnormal flowering mutant. Regeneran from anther culture was diploid, but two putative double haploids came up from multi ovule slice culture and ovary culture. Cytology and flow cytometry observations showed that seven haploid plants were obtained from pseudofertilization. Spontaneous chromosome doubling was inferred to have occurred during the callus culture period. In conclusion, gynogenesis through multiovule culture, ovary slice culture and pseudofertilization was more effective in inducing haploid and double haploid plants than androgenesis.
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Judul: Induction of haploid callus through anther cultured on citrus sp.
Abstrak: Anther culture is one method to produce haploid callus and plants. By the doubling of their chromosome, double haploid plants can be generated and used to produce F1 hybrids. Haploid callus can also be used as tissues for somatic hybriditation to produce triploid Citrus and other non-conventional breeding program. The objective of this research were to study microspore development of four Citrus spesies (Tangerine Garut, Tangerine Batu 55, Siam and Pamelo), effect of cold pretreatment, media type, and plant growth regulator on of callus induction from citrus anther. The development of microspores can be seen by measuring the ratio of the size of the sepals and petals flower. Microspores that have high percentage of uninukleat given different levels cold pretreatment to improve the ability to form callus. After treated with cold pretreatment, callus was induced with various formulations of media, resulting haploid callus then carried out chromosome counting. The results shown that the microspore uninucleat was highest (78,2% to 91,4%) in medium-size flowers with a ratio of the sepal: petal (1:4 - 2:6) mm in flower Tangerine Garut, Tangerine Batu 55, Siam Citrus, and (6:14 - 6:17) mm in flower Pamelo. Microspores uninucleat in Garut citrus flowers ranged from 78.2 to 91.4%, at tangerine Batu 55 flowers ranged from 78.2 to 85.6%, the citrus flower Siam from 79.4 to 90.5%, and citrus flower Pamelo ranged from 78.2 to 85.4% of the take total microspores. Cold pretreatment of anther for 5 days was able to inducted callus citrus keprok Garut up to 2%. MT medium + 3 mg / l BAP + 500 mg / l extract malt on solid media were able to induce callus 14.5% in tangerine Batu 55, while the treatment of liquid media is only able to induce callus up to 4.5%, and solid + liquid media treatments able to induce callus 3.6%. The data is observed when the culture aged 6 weeks after planting. The best medium to induce callus Siam Citrus are MT medium + 3 mg / l 2,4-D + 500 mg / l extract malt, is able to induce callus up to 1,6%. MT medium with 3 mg/l BAP and with 1 mg/l NAA was able to induce callus Pamelo up to 2,6%. Chromosome counting is performed to determine ploidy level of callus produced. The result showed that all chromosome of the anther derived callus was 9 as half of diploid chromosome.
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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