Slow-growth in vitro conservation of potato germplasm at normal propagation temperature

Summary In-vitro conservation of microplants at 24±1 °C was investigated in six potato genotypes belonging to different maturity groups. Growth was controlled by using different concentrations of sucrose (20, 40 and 60 g 1⁻¹) alone or in combination with either mannitol (20 and 40 g 1⁻¹) or sorbitol (20 and 40 g 1⁻¹) in Murashige and Skoog medium. Maximum microplant survival (55.5–77.8%) after 12 months of storage was on medium supplemented with 20 g 1⁻¹ sucrose plus 40 g 1⁻¹ sorbitol. Microplants so conserved were in good to very good condition, without phenotypic abnormalities and had enough nodes for sub-culturing. Microplant survival and microplant condition were closely associated with each other but not with root growth. The success of conservation was unaffected by maturity group of the genotypes. This conservation approach at 24±1 °C can be an effective alternative to low temperature (6–8 °C) storage, especially in tropical and sub-tropical conditions, where the ambient temperatures in summer can reach 45–50°C.