MEASUREMENTS OF INTERNAL ETHYLENE CONCENTRATION AND STUDIES OF ITS EFFICACY AS A PREDICTOR OF EMPIRE APPLE STORAGE LIFE

Mean internal ethylene concentration (IEC) was determined for 708 10-to 60-apple samples in seven seasons. When IEC of the first five apples in a sample ≤0.10 ppm, more than 90 percent of the sample means were also ≤0.10 ppm and 100 percent were ≤0.20 ppm. Although mean IEC was similar when determined by individual fruit measurements and by measurements of bulked samples, occasional discrepancies precluded further use of bulked samples for GC analysis of IEC. Best harvest dates for storage occurred after the initiation of the ethylene climacteric. IEC at harvest was not correlated with best harvest dates for storage in two seasons, nor was IEC a useful predictor of potential storage life for apples delivered to storage in three seasons. Keeping quality appeared to be more strongly influenced by orchard factor(s) than by small differences in fruit maturity (IEC) at harvest.