The field experiment was conducted to study the effect of foliar application with 25 and 50 ppm naphthalene acetic acid and 2 and 4 g/L yeast extract and their combinations on some growth aspects, photosynthetic pigments, minerals, endogenous phytohormones, flowering, pollen grain fertility and fruit yield and quality of tomato cv. Super Strain B under summer conditions during 2009 and 2010 seasons. Plants were sprayed three times at 30, 45 and 60 days after transplanting. Results indicated that the different applied treatments significantly increased all studied growth parameters (number of branches and leaves, leaf area and leaf dry weight as well). Besides, the two concentrations of each applied yeast extract or naphthalene acetic acid obviously increased photosynthetic pigments, N, P, K, Fe, Zn, Mn, total carbohydrates and crude protein concentrations in leaves of treated plants as compared with those of untreated ones. Also, all treatments increased auxin, gibberellin and cytokinin levels in tomato shoots at 75 days after transplanting during 2010 season whereas abscisic acid was decreased. Furthermore, the highest fruit set, early and total yields were obtained with 4 g/L yeast extract plus 50 ppm naphthalene acetic acid. In addition, chemical composition of minerals and some bioconstituents such as carbohydrates, vitamin C and total soluble solids in tomato fruits were also increased at the same treatments. Therefore, the present study strongly admit the use of naphthalene acetic acid and yeast extract as foliar application not only to increase early and total yields but also getting a good fruit quality as well, under summer conditions. |
