Application of Soluble Chitosan in vitro and in the Greenhouse to Increase Yield and Seed Quality of Potato Minitubers

Abstract

The aim of this work was to investigate whether the application of soluble chitosan in potato micropropagation can improve microplant quality in vitro, help acclimatisation ex vitro, and increase yield and seed quality of minitubers. Potato cv. Desiree microplants were treated in vitro with soluble chitosan added to the semisolid tissue culture medium in different concentrations. Microplants were subsequently transferred to the greenhouse and sprayed with chitosan solutions or remained unsprayed. Untreated microplants were also established ex vitro and sprayed with chitosan, or left unsprayed as a control. Morphological and physiological parameters of plant growth were assessed in vitro and ex vitro. Plantlet quality was evaluated using a ranking system. Minitubers derived from greenhouse plantlets were planted in the field in subtropical conditions, and growth and yield parameters evaluated. The chitosan concentration most beneficial to the in vitro growth of microplants varied between years. In treatments with the best in vitro growth, minituber number and yield in the greenhouse was also increased. Foliar chitosan application at the acclimatisation phase stabilised the effect of in vitro treatment on yield parameters. The seed quality of minitubers derived from chitosan treatments in vitro alone and in combination with foliar treatment at acclimatisation was improved, giving rise to field plants with increased tuber numbers and yields. The combination of chitosan in vitro and foliar application during the acclimatisation phase ex vitro had a greater effect on minituber seed quality than the concentration applied in vitro.