Meristem Culture Method for Virus Elimination from Shallot Bulb

Meristem Culture Method for Virus Elimination from Shallot Bulb Shallot farmers in Indonesia have commonly grown bulbs from the previous planting season as seed sources for the next season. This may cause the accumulation of viruses in bulbs which in turn lowering plant productivity. A research was conducted to optimize the meristem culture method combined with thermotherapy (30 ºC) to produce virus-free shallot bulbs. Shallot bulbs of cv. Bima Curut that had been confirmed infected by Potyvirus and Carlavirus were used as explant sources. Bulb sterilization was carried out using bactericides, fungicides, and sodium hypochlorite. Meristem shoots of 0.6 to 0.7 mm in size were isolated from bulbs and plant successively in the shoot, root, and bulb induction medium to form mini bulbs. The mini bulbs were then planted in the screen house for 2 to 2.5 months until micro bulbs were formed. Virus detection by reverse transcription-polymerase chain reaction method confirmed that plantlets at the multiplication stage and plants in the screen house were free of Potyvirus and Carlavirus infestations. This study showed that the meristem culture method combined with thermotherapy is a potential approach for producing virus-free shallot bulbs.Petani bawang merah di Indonesia menggunakan umbi hasil panen sebagai sumber benih untuk musim tanam berikutnya. Hal tersebut dapat menyebabkan akumulasi virus pada umbi meningkat dan menjadi penyebab terjadinya penurunan produktivitas tanaman. Penelitian dilakukan dengan tujuan mengoptimasi metode kultur meristem yang dikombinasikan dengan teknik termoterapi (30 ºC) untuk menghasilkan umbi bawang merah yang bebas virus. Umbi bawang merah cv. Bima Curut yang sudah dikonfirmasi terinfeksi Potyvirus dan Carlavirus digunakan sebagai bahan eksplan. Sterilisasi umbi dilakukan secara bertahap menggunakan bakterisida, fungisida, dan sodium hipoklorit. Tunas meristem berukuran 0.6 sampai 0.7 mm diisolasi dari umbi dan ditanam berturut-turut pada medium penginduksi tunas, akar, dan umbi sampai terbentuk umbi mini. Umbi mini selanjutnya ditanam di rumah kasa sampai terbentuk umbi mikro. Hasil deteksi virus dengan metode reverse transcription polymerase chain reaction mengonfirmasi bahwa plantlet pada tahap multiplikasi dan tanaman di rumah kasa bebas dari infestasi Potyvirus dan Carlavirus. Penelitian ini menunjukkan bahwa metode kultur meristem yang dikombinasi dengan termoterapi potensial menghasilkan umbi bawang merah bebas virus