Three years ago we established a long-term cryogenic storage project for apple germplasm and utilized grafting of buds obtained from stored dormant shoot sections as the major viability assay. Grafting, however, is time consuming and requires considerable skill. Electrolyte leakage and oxidative browning tests were used as alternative viability assays. Using leakage from individual buds in a multiwell analyzer, we examined modifications of the electrolyte leakage test and analyzed the kinetics of leakage in an attempt to determine whether the test can predict grafting success. The results suggest that more buds were viable than were estimated by the grafting test. In vitro culture is being examined to test this and to determine if practical recovery is feasible for diversity within the germplasm collection.
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