The effect of CaCl2, MgSO4 and KH2PO4 on micropropagation and minitubrization on potato (Solanum tuberosum L.)

Background and objectives: Potato (Solanum tuberosum L.) is the most important food plant and the fourth most important crop in the world. Potato micropropagation can be affected by some factors including the composition and amount of salt of ulture medium c. In this study, the effect of increasing in macro element including CaCl2, MgSO4 and KH2PO4 in culture medium on micropropagation and tuberization of potato using three Agria, savalan and Marfona cultivars in MS medium were examined.
Materials and methods: To investigate the effect of different concentration of CaCl2, MgSO4 and KH2PO4 on plantlet growth, three separate experiments were performed with four levels (1, 1.25, 1.5 and 1.75 times as much of base MS medium). Each experiment was performed according to the a completely randomized design (RCD) layout with ten replication. After 30 days, the different traits were measured including shoot length per plantlet, mean of root length per plantlet, number of roots per plantlet, leaf size per plantlet, number of nodes per plantlet and mean of minituber weight per plantlet. Then the regenerated plants were acclimatized and cultured in the field conditions in Damavand city for minituber production and the end of growing season number of minitubers per plant and mean of minituber weight per plant were measured.
Results: The results of increasing CaCl2 in culture medium indicated that the increasing this salt in medium some traits including shoot length per plantlet and mean of root length per plantlet was improved. The result of the effect of KH2PO4 in medium culture indicated that by using most of the salt concentrations in the culture medium, most of the studied traits were significantly better. Also, the use of high concentrations of MgSO4 in the culture medium significantly improved the studied traits.
Conclusion: In general results indicated that the increased of this concentration in macro element in medium culture have significantly increased mean of root length per plantlet, number of roots per plantlet, shoot length per plantlet, number of shoots and number of nodes per plantlet in contrast with control which leads to increased micropropagation rates and save on labor and time. The increased of mean of root length per plantlet and number of roots per plantlet led to fewer plants adapted to be removed. However, in most cases increasing in concentration of macro element in culture medium did not improve number of minitubers per plant and mean of minituber weight per plant.