Non-destructive monitoring of maturity of peach fruit and grape berry on trees with a portable vibrating-device

The softening process of fruit on trees was non-destructively monitored by a portable vibrating device to predict harvest times for four cultivars of peach and véraison of grape (‘Shine Muscat’), since the fruit firmness corresponds to its maturity.
Second (f₂) and third resonant frequency (f₃) of the peach fruit and grape berry on trees were continually measured from the immature stage to the harvest time.
Declining curve of fruit firmness was simulated by the reciprocal equation:

y=a×1-xb-cx

where y is fruit firmness, x date, and a, b and c are the coefficients (Terasaki et al., 2006). Fruit firmness (y) was estimated by a square of f₂ or f₃. The equation significantly simulated all the fruit softening curves.
Using the equation shown above and three obtained coefficients, an appropriate harvest time for peach can be predicted at least 9 days before harvest.
The véraison of the grape can also be predicted by the equation for an appropriate timing of shoot pinching that is necessary for improving the fruit quality.
Analysis of daily changes in grape berry firmness on trees revealed that the firmness was lowest at midday, and highest early in the morning.

IV Asian Horticultural Congress – AHC2023

N. Sakurai, T. Hino, M. Kawamura

fruit firmness, grape, harvest, maturity, peach, véraison, vibration

https://doi.org/10.17660/ActaHortic.2024.1404.5