PREDICTION OF DAYS AFTER ANTHESIS OF DEVELOPING TOMATO (<i>SOLANUM LYCOPERSICUM</i>) FRUIT FROM BLOSSOM-END CHANGES IN COLOR

Abstract

The development of mathematical models to predict the physiological status of a developing fruit can b e a useful tool to reduce the variation in fruit respon se to postharvest treatments. The objective of this study was to develop a mathematical model to predict Days After Anthesis (DAA) in tomato fruit from changes in the blossom end color. Around 160 tomato flowers from 40 plants of a tomato cultivar ‘Rutgers’ and the nea rly isogenic line tomato ripening mutant rin were tagged after artificial pollination and allow ed to fruit set. The quantification of color was done from 5 to 85 DAA every 5 days in the tomato fruit blossom-end of both ‘Rutgers’ and mutant rin using a a Minolta chroma meter CR-300 set in the L*, a* and b* color space. The predictive model was developed using the stepwise procedure in forward selection with DAA as the respo nse variable and all the possible combinations between the next group of regressor: L*, a* and b*, square L*, a* and b*, chroma and Hue angle calculated from measured a* and b* values. It was used the F statistic, m ean square error, coefficient of determination, Mallows coefficient and distribution of residuals around z ero as indicators of model prediction’s efficiency. Correl ation coefficients between the different variables measured and the DAA were calculated. The reliability of the statistical analysis was tested by using the nearl y isogenic line of ‘Rutgers’: The non-ripening mutant rin as a comparative control. It was concluded that th e statistical procedure used is robust and sensitive enough to id entify data not suitable for developing a good pred ictive model. Also, it is possible to predict the days aft er anthesis of a developing tomato fruit from chang es in the blossom-end color with almost 80% of accuracy.