Volume 16(1), 232-238, 2012 JOURNAL of Horticulture, Forestry and Biotechnology www.journal-hfb.usab-tm.ro 232 Production of virus free potato plantlets Danci M., 1* Danci Oana 1 , Mike Luiza 2 , Baciu Anca 2 , Olaru Daniela 1 , Petolescu Cerasela 1 , Berbentea F. 1 , David I. 1 1 Banat’s University of Agricultural Sciences and Veterinary Medicine Timişoara; 2 Potato Research and Development Station – Targu Secuiesc, Romania *Corresponding author. Email: marcel_research@yahoo.com Abstract Potatoes a high susceptibility to viral, bacterial and fungal diseases impose production of virus free material for healthy seed production since plant viruses are pathogens that cannot be destroyed by using plant protection chemicals. Meristem tip culture technique is one of the most used for potato in vitro culture initiation and is most of all used in order to obtain virus free plantlets. For this study six new Romanian potato cultivars were used. Explants were prepared for tissue culture and half of them underwent chemical (using the antiviral chemical-ribavirin) treatement. Culture tubes were incubated at 20-21 o C in 16 hr photoperiod with 2000 lux light intensity for 6-8 weeks. Leaf samples of 10 plantlets of each cultivar were tested for viruses: PVS, PVY, PVX and PLRV by ELISA technique. Virus-free individuals were measured for several biometrical parameters and subcultured on fresh multiplication media for 4 weeks. Best virus free production was obtained after Ribavirin treatment even if regeneration capacity after chemical therapy decreased with around 10%. Key words meristem tip culture, virus- free plantlets regeneration, virus indexing, Solanum tuberosum L., Ribavirin Potato is one of the most important food crops in the world and especially in our country. In Romania, after wheat, potato is the second most important food crop being very important for alimentary and chemical industry and also in animal feat, due to its richness in vitamins (especially vitamin C), hydrocabonates, and starch (). It is used in alimentary industry, alcohol production and animal feeding. Potato can be propagated sexually (by botanical seed, also called true potato seed) and asexually (vegetatively) by means of tubers (Otroshy, 2006). Propagation by tubers is a conventional system used by farmers. There are two major problems associated with vegetatively clonal multiplication of potato-seed stocks. Firstly, low multiplication rate in the field takes as long as 7 to 12 years, causing a lack of flexibility to the changing needs of the end-users. Secondly, potatoes present a high susceptibility to viral, bacterial and fungal diseases (Loebenstein et al. 2001). Plant viruses are pathogens that cannot be destroyed by using plant protection chemicals. The use of virus-resistant varieties (or eradicated disease-free initial seed production material) is preferred for avoiding crop yield or quality losses. Nowadays, micropropagation is the alternative to conventional propagation of potatoes (Danci et al., 2011), being used as standard methodology for production of disease free (virus free) seed potatoes without or with chemotherapy (Faccioli and Zoffoli , 1998). It is known that meristem culture is the only way to obtain virus free biological material (Loebenstein et al. 2001). Meristem tip culture was first used to produce virus- free plants (Huang and Murashige, 1976) since meristem is domes of actively dividing cells, located at the apices of shoots and roots, that remain in an active state of division throughout the vegetative phase of the plant, forming new tissues and organs (shoots, leaves, roots); they have therefore the capability of producing complete plants in vivo and in vitro (Danci, 2007). This totipotency is the basis of the meristem tip culture technique. Virus particles, which may be present in the vascular system, can reach the meristematic region of the apex only through cell to cell movement (Carrington et al, 1996); a slow process that might take within a few days (Hull, 2002). This is one of the main reasons why in a virus infected plant, virus concentration decreases acropetally toward the meristem of both the apical and the axillary buds (Lizarrago et al. 1991), on assumption that viruses were unable to invade the meristematic tissues of the bud.. The in vitro technology combined with traditional methods can increased the commercial production of virus-free seeds an important pre-requisite to maximize yield in potato. Potato is also the first major food crop where biotechnology has been successfully applied for virus elimination (Bajaj and Sopory, 1986). Literature reports showed that root tips of plants infected with one of several viruses have been found to be free of detectable virus (Appiano and D’Agostino, 1983). Smith and Schlegel (1964) studied the distribution of Clover yellow mosaic virus in root tip of Vicia faba and found that within the limit of the assay method, the first 0.4 mm of the root tip, which included the root cap and the meristem, were virus free. Thus, the optimum