METHOD: Ion Leakage CONDITIONS: Biotron - 14h light at 18-20C or 2-4C with 70% RH METHOD NARR: Freezing tolerance was measured by gradually lowering leaflet temperature in a glycol bath and measuring ion leakage. Measurements weion leakage curve. Rates of deacclimation were also measured. RESULTS NARR: Four types of acclimators were observed: 1- early acclimators that showed 40-50% acclimation within days 1-3; 2- late acclimators gained the majofter at least 6 days of cold treatment; 3- progressive acclimators showed a steady increase of cold acclimation over time; 4- nonacclimators showed no acclimation ability. The extent of deacclimation during 12h at 18C varied frdeacclimators to high (over 60%) in rapid deacclimators. AUTHOR EXPLANATION: Rates of cold acclimation and deacclimation are not necessarily related to the acclimation capacity of the species. Ideally one would want to have rapid adeacclimation incorporated into the same plant for breeding purposes. Mga subsp. tor is the best choice of those tested.