Comparison of methods for estimating the onset of the respiration climacteric in unpicked apples

Abstract

SummaryThe rate of deterioration of apples in storage is influenced by their maturity at harvest. Three methods based on the occurrence of the rise in ethylene production which is coincident with the climateric rise in respiration, have been used to assess the maturity of the crop for various apple cultivars.In the first method internal ethylene concentrations (IEC) were measured in fruit samples soon after picking at weekly intervals. The onset of the climacteric was defined as the date when the internal concentration passed 0.1 μ l-1. The other two methods were based on ethylene production by bulk samples picked at weekly intervals. In one, the mean delay between picking and the rise in ethylene production (DEP) was calculated, and the other recorded the first date on which at least half the replicate samples showed immediate ethylene production (IEP).The dates determined by IEC and IEP were generally in agreement for each cultivar but there was little evidence of correlation in respect to site and seas...