Eliminasi Onion yellow dwarf virus melalui Kultur Meristem Tip pada Bawang Merah (Allium ascalonicum L.)

<p>ABSTRACT<br />Meristem tip culture is culture of isolated meristem with 1-2 leaf primordia on suitable medium. This method is generally used to obtain free virus plant. Optimation of plant growth regulators (PGRs) was done to accelerate explant growth without callus formation and to avoid somaclonal variation in meristem tip culture. The aims of this study were to achieve the best combination of PGR for meristem tip growth and to evaluate meristem tip culture potential for Onion yellow dwarf virus (OYDV) elimination in shallot. This study used combination of PGRs 0.25 mg L-1 (2-ip, BAP, GA3, kinetin) with or without 0.1 mg L-1 IAA and medium without PGR. This research consisted of two experiments conducted separately. In experiment I, cv. Bima Brebes was used and experiment II cv. Tiron was used. Each experiment was arranged in completely randomized block design with single factor (PGR combination) that has 8 combination levels and 3 replications. The result showed that medium without PGR was the most efficient for meristem tip growth. Primary shoot was growing without callus formation. RT-PCR analysis showed that all of the tested samples were still infected by OYDV. Meristem tip culture method did not eliminate OYDV in both cultivars.<br />Keywords: Auxin, cytokinin, GA3, OYDV, RT-PCR</p><p>ABSTRAK<br />Kultur meristem tip merupakan kultur meristem yang diisolasi 1-2 primordia daun dan pada media yang sesuai. Metode ini umum digunakan untuk mendapatkan tanaman bebas virus. Optimasi terhadap zat pengatur tumbuh (ZPT) dilakukan untuk mempercepat pertumbuhan eksplan tanpa disertai pembentukan kalus untuk menghindari terjadinya variasi somaklonal pada kultur meristem tip. Penelitian ini bertujuan untuk mendapatkan kombinasi ZPT terbaik bagi pertumbuhan meristem tip dan untuk mengevaluasi potensi kultur meristem tip dalam mengeliminasi virus Onion yellow dwarf virus (OYDV) pada tanaman bawang merah. Penelitian ini menggunakan 0.25 mg L-1 (2-ip, BAP, GA3, kinetin) dengan penambahan atau tanpa 0.1 mg L-1 IAA serta media tanpa ZPT. Penelitian ini terdiri atas 2 percobaan terpisah. Percobaan 1 menggunakan cv. Bima Brebes dan Percobaan 2 menggunakan cv. Tiron. Masing-masing percobaan disusun berdasarkan rancangan kelompok lengkap teracak (RKLT) dengan 1 faktor, yaitu kombinasi ZPT yang terdiri atas 8 taraf kombinasi dan 3 ulangan. Hasil yang didapat menunjukkan bahwa media tanpa penambahan ZPT<br />merupakan media yang paling efisien untuk pertumbuhan tunas meristem tip. Tunas utama tumbuh tanpa disertai pembentukan kalus. Hasil analisis RT-PCR menunjukkan bahwa seluruh sampel yang dideteksi masih terinfeksi OYDV. Metode kultur meristem tip belum dapat mengeliminasi virus OYDV pada kedua kultivar bawang merah.<br />Kata kunci: Auksin, GA3, OYDV, RT-PCR, sitokinin</p>

In vitro meristem-tip culture and regeneration approaches in Congolese cassava accessions (Manihot esculenta Crantz cv. Boma and cv. Mpelo-Nlongi)

<p>Shiny dome-like structures measuring less than 1mm in length were excised aseptically from shoot tip buds of infected of two cassava (<em>Manihot esculenta</em> Crantz) local cultivars (Boma and Mpelo Nlongi) and cultivated <em>in vitro</em> in two types of media with different combination of growth hormone: Murashige and Skoog supplemented of sucrose (20 g/l), Naphtalenacetic acid (NAA, 10 μM), Ben-zylaminopurine (BAP, 0.66 μM) as well as Gibberellic acid (GA3, 0.1 μM) with 80 mg/l of Adenine sulphate and MS-free growth regulators. After four weeks, data were scored: 29.5% responding explant with callus formation and 20.5% responding explants to shoot development in the medium with growth regulators for the cultivar Boma whereas the cultivar Mpelo-Nlongi presented 5.7% and 25.7% respectively of callus formation and shoot development. The cultivar Boma presented a tendency more pronounced for the callus formation rather than with the shoot development contrary to the cultivar Mpelo-Nlongi. In regards of this experiment, it was shown that the media composition and genotype are essential factors, which influence in vitro growth, mainly the shoot development, in the culture of meristems for cassava local accessions.</p>