FOLIAR APPLICATION OF GLUTAMIC ACID IMPROVES YIELD AND PHYSICOCHEMICAL QUALITY PARAMETERS OF TOMATO FRUITS (Solanum lycopersicum L.)

Information on the application of single amino acids for plant growth and physiology is relatively scarce since most studies have only been concerned with mixtures of amino acids. The objective of this study was to evaluate the effect of glutamic acid applied to foliage on certain growth and physiological variables, physicochemical quality parameters of tomato (Solanum lycopersicum L.) fruit, and plant yield under greenhouse conditions. Treatments comprised 0.0 (control), 1.5, 6.0, and 12.0g.l(-1) glutamic acid and were conducted in a completely randomized design, including four treatments, four replications per treatment, and four plants per replication. Compared to the control plants, 167 days after transplant, SPAD values in tomato plants increased by 8.9 and 6.0% after applying 6.0 and 12.0g.l(-1) glutamic acid, respectively. Spraying 6.0g.l(-1) also increased plant yield 27.4%, equatorial fruit diameter 4.1%, fruit fresh weight 10.3%, and fruit dry matter 16.9%. Fruit pH increased 5.3% after using 1.5gl(-1) glutamic acid. Exogenous foliar application of glutamic acid favored the SPAD values, yield, and some physicochemical quality parameters of tomato fruits.