METHOD: Chemical Assay CONDITIONS: Field METHOD NARR: Two treatments were used. Calcium nitrate was used as a source of supplemental calcium which was applied 3 times. The treatment without extra calcium recieved an equivalentthe form of ammonium nitrate on the same three dates. Measurements of the calcium concentration in leaves were made using an atomic absorption spectrophotometer. Temperature was monitored throughout the field. RESULTS NARR frost were detected. There were highly significant differences among the accessions for both their ability to accumulate calcium and their frost tolerance. In general (but not always), a drop in frost score (increase in surviation of extra calcium. Frost damage was scored on a 1-6 scale with 1=no damage and 6=plant killed. AUTHOR EXPLANATION: The different response observed among the accessions suggests that even though some accessions are able to accy may lack the ability to benefit from the added calcium. Both sensitive and hardy species responded positively to supplemental calcium.