effects of ammonium to nitrate ratio and agar concentration on in vitro culture of carnation (dianthus caryophyllus l.) cultivar mondeo kgr

carnation is considered as the world's third most important cut flower. tissue culture techniques offer suitable method for micropropagation of this ornamental plant. however, one of the problems during in vitro culture of carnation is vitrification. ratio of ammonium to nitrate and agar concentrations in the medium affect this phenomenon. therefore, in this study the effect of these factors on the rate of proliferation and the vitrification of carnation (dianthus caryophyllus l.) cultivar innove orange bogr, was evaluated. in this investigation lateral buds were cultured on ms medium containing 1 mg/l ba, 0.1 mg/l naa and with different concentrations of agar and different ratio of ammonium to nitrate. the results showed that increasing in the agar concentration to 12 g/l lead to decreasing the rate of vitrification but regeneration also declined. increase of agar concentration cause limitation in nutrient absorption by plants. also, decrease in the ratio of ammonium to nitrate in the medium reduces the amount of vitrification, but did not result in adverse effects on plant regeneration rates. multiple regressions showed that the effect of ammonium to nitrate ratio on vitrification was higher than agar concentration. so by considering the amount of shoot regeneration and vitrification, to obtain the most normal shoots, the concentration of 10 g/l agar with ammonium to nitrate ratio 1:6, is recommended.