Ethylene Evolution from Apple Shoots and Spur Buds1

An effective and simple system for studying ethylene evolution from apple ( Malus domestica Borkh.) shoots was devised and used to follow seasonal patterns of ethylene evolution, as well as changes in ethylene evolution following ethephon and shoot bending treatments. Field studies using intact two year wood of spur and non-spur strains of ‘Delicious’ and ‘McIntosh’ showed similarly high levels of ethylene early in the season which subsequently declined. The large differences in ethylene evolution between sampling dates may have been caused by climatic differences at the time of sampling. No differences in ethylene evolution were detected among strains or cultivars although differences in flowering were observed in the following season.