Slow growth in vitro culture for conservation of Chilotanum potato germplasm

Manuel Muñoz1*, Oscar Díaz2, Waleska Reinún2, Annelore Winkler1, and Roberto Quevedo2
To keep potato (Solanum tuberosum L.) germplasm accessions disease-free and available for use, these are conserved as in vitro microplants under tissue culture conditions. The management of <em">in vitro plants is labor intensive due to the necessity of periodic transferring of explants to new containers and fresh medium (sub culturing). The effectiveness of MS medium supplemented with sorbitol or mannitol in conservation of potato germplasm corresponding to different genotypes from Chilean native landraces (Chilotanum group) was investigated. Growth curves for modelling, describing and predicting shoot elongation of in vitro potato plants through the time in different culture media were developed as a tool to plan subculture labor for refreshing explants to new media. In MS medium without osmotic active compounds the rate of shoot elongation (k) was 1.12-1.45 cm wk-1 with 0% mortality. In media supplemented with 20, 40, and 60 g L-1 sorbitol, k value ranged between 0.58-0.35, 0.42-0.27 and 0.09-0.05 cm wk-1, respectively. Mortality was 0%, 13%, and 26% for such treatments. In case of mannitol, k value ranged between 0.14-0.25, 0.065-0.11 and 0.042-0.068 cm wk-1 with 3%, 6%, and 26% mortality for 20, 40, and 60 g L-1, respectively. These data can be used to predict shoot elongation rate in different media that provide several alternatives of speed of growth. The information allows to design an adequate strategy for organizing the work in a potato germplasm bank of S. tuberosum, Chilotanum group.
Keywords: Growth modelling, mannitol, potato germplasm, Solanum tuberosum, sorbitol, tissue culture.
1Instituto de Investigaciones Agropecuarias, INIA Remehue, Ruta 5 Sur, km 8 Norte, Osorno, Chile.
*Corresponding author (manuel.munozd@inia.cl).
2Universidad de Los Lagos, Departamento de Acuicultura y Recursos Agroalimentarios, Campus Osorno. Fuchslocher 1305, Osorno, Chile.