PEACH FIRMNESS PREDICTION BY MULTIPLE LOCATION IMPULSE TESTING

Effe-gi firmness and acoustic impulse response were measured at four l ocations (2 sites per location) on the surface of two freestone peach cultivars, 'Loring' and 'Cresthaven'. The acoustical impulse response signal was interpreted by determining the energy content of the respon se signal between 150 to 200 Hz. The proportion of energy in this freq uency band, compared to the total energy content between 0 and 500 Hz, was used as a predictor of firmness and was termed BM150-200. Spatial variation of Effe-gi firmness was found to be very small for 'Loring' , but significant for 'Cresthaven'. Spatial variation of the parameter BM150-200 for both cultivars was significantly different for some sit es. Correlations between Effe-gi firmness and BM150-200 for single sit e or two-site average were generally good with the 'Loring' cultivar w hich had little spatial Effe-gi firmness variation. Equivalent correla tions for 'Cresthaven' peaches, which had significant spatial Effe-gi firmness differences between locations, were poor. Averaging Effe-gi a nd BM150-200 measurements from multiple test sites improved the correl ation between these parameters for 'Cresthaven' peaches.