Fruit water content: a benefit in the fruit carbohydrate accumulation simulation

Carbohydrates are major assimilates determining fruit growth and quality, either as raw materials for growth or as carbon reserves for quality. Fruit water content, an indicator of water status in fruit, is closely related to fruit carbohydrate metabolism. A process-based model (Génard and Souty, 1996; Génard et al., 2003) was adapted to simulate carbohydrate accumulation during fruit growth under different cultivation practices. Two models were developed by integrating the possible effect of fruit water content (Tom_SUGAR_WC) or not (Tom_SUGAR). Data were collected from three experiments on tomato, a model plant for fleshy fruit, of two genotypes ('Levovil' and 'Cervil') grown under different conditions. The first experiment was with standard conditions; the second with high and low fruit loads treatments; the third with full irrigation and water deficit treatments. Results from the studies were used to evaluate the models' performance. Compared to Tom_SUGAR, Tom_SUGAR_WC resulted in lower values of Akaike information criterion (AIC) and relative root mean squared error (RRMSE), showing that Tom_SUGAR_WC performed better than Tom_SUGAR in simulating soluble sugar and starch accumulation during the fruit growth under different conditions for both genotypes. Fruit water content with its potential influence on carbohydrate metabolism could bring benefit to the simulation of fruit carbohydrate accumulation.