LOGIT-MODELS FOR ESTIMATING LETHAL TEMPERATURES IN APPLE

Legit models were used to analyze freeze-survival data of apple (Malus domestica Borkh.). The effects of hardening and dehardening treatment s and two treatment durations bn lethal temperature were studied using two cultivars, The major benefits of logit models were 1) the form of the sampling variation in the qualitative response variable was taken into account, 2) the lethal temperatures could be estimated with conf idence intervals, and 3) the effects of treatments could be interprete d and compared easily using odds ratios. The momentary frost resistanc e estimates for 'Antonovka' and 'Samo' were -46 and -43C, respectively , Dehardening at 14C raised the lethal temperature by 12 to 15C, where as hardening at -15C did not affect the frost resistance of either cul tivar.