African Journal of Agricultural Research, Vol. 5(4), pp. 268-274, 18 February, 2010 Available online at http://www.academicjournals.org/AJAR ISSN 1991-637X © 2010 Academic Journals Full Length Research Paper In-vitro plantlet propagation and microtuberization of meristem culture in some of wild and commercial potato cultivars as affected by NaCl Mansoor Saljooghian Pour*, Mansoor Omidi, Islam Majidi, Dariush Davoodi and Parichehreh Ahmadian Tehrani University of Tehran, Faculty of Agriculture (Karaj), Department of Agronomy and Plant Breeding, P. O. Box 31578-11167, Iran. Accepted 9 November, 2009 The effects of in vitro salinity (NaCl) on plantlet growth, microtuberization and genetic diversity was investigated under saline and non-saline conditions using twelve cultivars (clones) of potato named Ranger-russet, AGB-69-1, MEX-32, Maine-28, Loman, Araucana INTA, Surena INTA, American-INTA, Aracy, FLS-5, Agria and Marphona, which were planted in the greenhouse. Young shoots were cut and transferred to tissue culture laboratory of agricultural biotechnology research institute. Apical and axillary meristems were cultivated on MS medium and samples were subcultured every four weeks on the same medium for plantlet production. Then plantlets were propagated through single nodal culture. To study the effects of salinity (NaCl) on the growth of single nodal explants and on microtuberization, cultivation on MS media with different concentrations of NaCl (0, 25, 50, 75 and 100 mol l -1 ) was carried out. Growth of single nodal explants on the saline media indicated that all the characters of the cultivars studied, the salinity levels and the studied interaction effects had significant difference at P < 0.01. These characters were also shown to have different responses to salinity levels. Microtuberization responses on different saline media was also different and indicated that all the studied characters, except the number of microtubers and the mean of minimum microtuber diameter, had significant difference at P < 0.01 for cultivars, salinity levels and interaction effects. Genetic diversity on the basis of microtuberization using analysis of cluster among potato cultivars and phenotypic correlations among characters under saline and non-saline conditions were also studied. Key words: Potato, tissue culture, microtuberization, salinity tolerance, genetic diversity. INTRODUCTION The salty ground water as well as the irrigating water (containing about 30 g/l of NaCl) tends to limit agricultural activities. However, the use of saline water for crop production is often unavoidable (Heur and Nadler, 1998). Generally, the salinity problem becomes more severe with more intense cultivation (Christiansen and Lewis, 1982). Salinity stress induces several alterations on plant growth, cell division and enzymatic activities, among others. Salinity tolerance of plants primarily depends on the genotype that determines alterations on processes such as uptake and transport of salts by roots, together with metabolic and physiological events occurring at *Corresponding author. E-mail: Mansoor_781@yahoo.com. cellular level (Winicov, 1993). A large volume of data has been published on the subject of plant responses to salinity. Salt tolerance is actually a complex phenomenon (Martinez et al., 1996). For the improvement of plants, various techniques have been developed. Novel breeding methods such as somaclonal variation, interspecific hybridization, somatic hybridization and gene transforma- tion provided potential for improving important commer- cial characters. Today, these unconventional breeding methods combined with conventional methods are used as powerful tools in plant breeding programs by an enormous number of researchers (Turhan, 2005). Plant tissue culture techniques involve the growing and multiplication of totipotent cells, tissues and organs of plants on defined solid or liquid media comprising nutrients under an aseptic and controlled environment