|dc.description.abstracteng||Tomato (Solanum lycopersicon L.) is the most important vegetable in the world consumption and production. The fruits significantly contribute to human health, as they are rich in vitamins, minerals, sugars and antioxidants. Therefore, the high demand on tomato fruits consumption as fresh and processed products necessitates yield increase. However, the focus on yield increase does not consider the fruit’s flavor and might dissatisfy the consumers. Most of the consumers store tomatoes after purchasing in household fridge, which decreases the quality and the flavor of these fruits. Nevertheless, an application of particular cultivation management such as optimized plant nutrition could enhance fruit yield and quality. Potassium (K), as one of the essential mineral plant nutrients, is crucially involved in tomato production and fruits quality and has the potential to ameliorate them. It also has a major role in plant-water-relations, e.g. on water-use efficiency WUE. The objectives of the present study were to evaluate the effect of K on the yield production, postharvest behavior, and sensory profile of different tomato cultivars.
The effect of K on yield and water-use efficiency (WUE) was investigated in an outdoor pot experiment with two cocktail tomato cultivars Primavera and Yellow Submarine and six K levels from deficiency to overdose. To study the fruit postharvest behavior, another outdoor pot experiment was conducted with two K levels (K low and K high) and two boron (B) levels (B low and B high) on the same cultivars. The breaker fruits were stored at two different conditions: ambient conditions (20 °C) and refrigerated + ambient conditions (4 °C + 20 °C). In a third outdoor pot experiment, the effect of K on the sensory profile of the fruits was studied at three different K levels (named as K low, K moderate and K high) on three tomato cultivars as Lyterno, Primavera and Yellow Submarine. The sensory evaluation was performed by panelists and subsequently, the taste-related analyses were assessed.
The yield and WUE increased significantly with rising K but they were declined with K overdose. Similarly, the fruit quality attributes as color, total soluble solids (TSS), titratable acids (TA) and dry matter (DM) increased significantly with K application but further supply to overdose did not reveal any enhancement. The effect of K on the fruit’s postharvest behavior exposed as a significant increase in TSS, TA and DM in both storage regimes. Boron did not show any significant increase on the studied parameters in this experiment. Potassium had a significant influence on the taste-related attributes and some of the sensory traits but not on fruit volatile compounds.
Generally, optimal K application enhanced the yield, WUE and the fruit quality attributes, while excessive K application did not possess a significant increment effect. The combination of high K and low B fertilization improved the fruit quality performance only under ambient storage conditions. The positive effect of K on the fruits sensory profile was confirmed to be detectable by the human senses as well as with the instrumental analyses.
The conclusions drawn from this study are: that an optimal application of K fertilization on tomato ensures high yields with less water consumption moreover enhances the fruit quality attributes. The adequate application of K on tomato plants reinforces the development process during postharvest of the fruits, which influence positively on the fruit quality under storage conditions. Furthermore, K is important to enhance the flavor of tomato fruits and meet the consumer’s preferences. The present study indicates that potassium nutrition is one of many factors that can influence tomato growth and its potential to enhance yield, fruit quality and WUE essentially depends on all factors’ integration.||de