Abstract
Quality of tomato fruits can be improved by applying water stress. To avoid the excessive yield reduction and high blossom-end rot incidence, it is highly important to apply water stress at an optimum level. In this research, a calibration model for nondestructive determination of leaf water potential (LWP) was developed using near infrared spectroscopy. A tomato leaf was cut and its spectra in transmittance mode at six different positions were immediately measured. The LWP was determined simultaneously using the pressure chamber method just after spectral acquisition. The result showed that the best calibration model was identified for spectra in wavelength range of 700-990 nm with R2=0.86 and standard error of calibration=0.076. The validation result showed that its calibration model had low bias and low SEP. By a 95% confidence pair t-test, there were no significant differences between the LWP measured using the pressure chamber method and that predicted by near infrared spectroscopy. This result showed that determination and monitoring of the LWP values using near infrared spectroscopy are possible and can be used for water stress management with high accuracy.
