Effects of different conservation methods on the genetic stability of potato germplasm

Authors:
  • GYG. K. Yin
    G. K. Yin

Abstract
A total of 50 potato (Solanum tuberosum L.) varieties were maintained in vitro or under field conditions at Keshan National Genebank (KNG) for 15 years. At the end of the conservation period, a two-year field trial was conducted to evaluate the effect of conservation methods on the genetic stability of accessions, using agronomic characters, isoenzyme markers, and DNA molecular markers. None of the 50 varieties maintained under field conditions had completely preserved agronomic characters. Plants kept in vitro demonstrated still lower level of stability than those conserved under field conditions. Differences in the isoenzyme electrophoresis patterns were found in ten of the varieties tested. The SSR (simple sequence repeat) analysis indicated genetic variation between each variety maintained in vitro and under field conditions and showed the genetic similarity coefficient ranged from 0.735 to 0.993. Three of the accessions maintained in vitro and under field conditions did not cluster together. The results suggest that the genetic stability of varieties maintained under field conditions was higher than those maintained in vitro. Therefore, in order to maintain the genetic integrity of potato germplasm resources, field conservation should be used for long-term conservation of potato germplasm collections, and the genetic stability should be checked regularly.

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