The effect of two hydroponic systems on physical, chemical and fruit yield of two greenhouse tomato cultivars

Tomato is an economical high value product which is used fresh or processed. Having compound such as fibers, vitamin A, vitamin B, lycopene, carotenoids, ascorbic acid and polyphenols in this product leads to prevent the cancer and cardiovascular diseases. Even though biosynthesis and accumulation of this biochemical matter in tomato fruit when growing is affected by the production conditions such as methods of production environmental factors and plant genetics. Tomatoes produced in a closed hydroponic system have better flavor and marketability. This research is done to show the affects to the physical and chemical characteristics and productivity of two greenhouse tomato cultivars in two open and closed systems.

In this research the effects of two open (drip) and closed (modified nutrient film technique) hydroponic systems on physical and chemical characteristics and productivity of two greenhouse tomato cultivars (V4-22 cultivar breaded in Shahid Chamran University of Ahvaz and Amira cultivar from Rijkzwaan company of Netherland) was studied as split plot based on a randomized complete block design with three replications in agricultural faculty of Shahid Chamran University of Ahvaz. The information gathered and correlation between characteristics were analyzed statically by MSTAT-C 1.2 software. To compare the means, Duncan's multi domain test in 5% level was used. Some of the quantitative and qualitative characteristics include productivity, fruit length, fruit diameter and fruit volume, fruit firmness, pH, titratable acidity, total soluble solid, fruit dry matter, lycopene, fruit carotenoids, antioxidant capacity, polyphenols content, concentration of fruit elements such as potassium, sodium, calcium and magnesium were analyzed.

The results of the experiment showed that the most fruit length, fruit firmness, and calcium concentration were recorded in the plants cultivated in open system and the highest total soluble solid, lycopene, carotenoids and fruit sodium concentration were seen in the closed system. The most antioxidant capacity, polyphenols content, concentration of calcium and sodium were observed in Amira cultivar and the most titratable acidity was recognized in V4-22 cultivar. The maximum yield belonged to V4-22 cultivar (3847/29 g per plant) and minimum yield belonged to Amira cultivar (3648/70 g per plant). The interaction effect of hydroponic system and cultivar on concentration of magnesium and potassium in 1% level and dry matter in 5% level were significantly different. The correlation between Antioxidant capacity, fruit total soluble solids content, vitamin C, lycopene and polyphenols content with potassium concentration was positive and significant.

The results showed that V4-22 cultivar had higher yield than Amira cultivar and this is due to the adaptation of this cultivar to the environmental conditions of Ahvaz greenhouse. In this study, crop yield in both open and closed systems was not significantly different and the closed system increased the quality characteristics of fruit including total soluble solids, lycopene and carotenoids compared to the open system. This can be due to the most availability of nutrient solution in the closed system compared to the open system. The lowest capacity of antioxidant and total polyphenols were obtained in V4-22 cultivar. The decrease in production of these secondary metabolites indicates that this cultivar is more compatible with production conditions.