Storage temperature and fruit calcium alter the sequence of ripening events of 'd'Anjou' pears

Pear trees (Pyrus communis L.), cv, d'Anjou, received foliar applications o f X-77 surfactant and 32.3 mM CaCl2 at 55, 85, 125, and 137 days after full bloom (DAFB) and fruit were harvested at: 147 DAFB. Samples of fruit mere stored in air either at 20 degrees C continuously or at 5 or 10 degrees C f or several periods, then transferred to 20 degrees C, to determine the effe cts of storage temperature and CaCl2, treatments on the development of the ethylene climacteric and flesh firmness loss. Control fruits held continuou sly at 20 degrees C required 70 days for the onset of climacteric ethylene production, which commenced when firmness had decreased to approximate to 2 0 N. Calcium-sprayed fruit required 80 days at 20 degrees C before the rise in ethylene and resisted softening for approximate to 50 days. Regardless of calcium treatment, pears stored at 5 or 10 degrees C required only 40 da ys to produce climacteric ethylene; fruit softening and internal ethylene c oncentration after storage at 10 degrees C were intermediate between those of fruits stored at 5 and 20 degrees C. Calcium application did not alter t he sequence of ripening events.