Evaluation of Different Starches as Gelling Agents for Micropropagation of Potato

Unavailability of clean planting material is a major constraint of potato production in Eritrea. In vitro multiplication is proved to be a reliable solution; however, due to high media cost and initial investment, its use has been limited. The current study was carried out to evaluate the effectiveness of three starches (corn, potato and barley) of both laboratory and commercial grades as agar substitute, for micropropagation of potato. Single nodes of potato were sub-cultured into a fresh modified Murashige and Skoog (MS) medium supplemented with sucrose (3% w/v) and gelled with 50 g/l of six types of starches in addition to 7 g/l of agar as a control. Gelling agents used showed a highly significant difference in all measured parameters. The pH of all starch based media increased by 0.23-1.3 units during the culture time except the control media which decreased by 0.4 units. Similarly EC showed a decreasing trend in all gelling agents. In most of the measured physical parameters such as plant height, root length, fresh weight and dry weight three starch based media namely laboratory grade potato, commercial corn and laboratory corn showed better results compared to the control media. Survival of in vitro plantlets ranged between 85 and 90% after acclimatization. Both laboratory and commercial grade starch based media resulted in cost reduction of 15-22% and 61-66%, respectively. This implies that using both corn and potato starches can be reliable and cost effective gelling agents for micropropagation of potato.