Effects of Nitrogen and Potasium on in vitro Microtuberization of Potato (Solanum tuberosum L. var Agria)

Optimum concentrations of nitrogen and potassium on in vitro microtuberization of Agria, a popular variety of Potato, Solanum tuberosum L., were evaluated. The concentrations of 0, 0.5, 1, 1.5, and 2 folds of standard concentrations of NH4NO3 (1650 mgl) and KNO3 (1900 mgl) were used in Murashige and Skoog (MS) medium, and their effects were studied on cell number, cell sizes, and number of amidon granules in skin and core parenchyma. A significant difference was observed in histological features of the microtubers developed in media containing different concentrations of macronutrients. KNO3 with concentrations of 1.5 folds of the standard concentration yielded maximum number of cell rows and sizes. However, an increase in potassium concentration beyond 1.5 fold decreased the cell and row numbers of microtubers. Different concentrations of potassium up to 1.5 folds did not affect the amidone granules but concentration more than 1.5 fold again decreased amidone granules content. Number of cells/rows and amidone content were reduced with an increase in nitrogen level up to 1 and 1.5 folds respectively. The results of this study could be applied in sexual propagation of potato in industrial and laboratory scales.