effects of concentration and spraying time of phenyl-phethalamate acid (auxin synergist) on yield of tomato, cucumber, eggplant and cabbage under field conditions

to determine effects of phenyl-phethalamate acid on yield and yield components of tomato, cucumber, eggplant and cabbage, this experiment was investigated in a randomized complete block design with three replications in the spring and summer of 2010. treatments included the time and number of foliar spraying with phenyl-phethalamate acid (1000 ppm). control plants were not sprayed. the first step of foliar spraying was the start of flowering. next sprays were repeated three times and 4 times for cucumber 15 days intervals. according to results, foliar spraying at flowering time had the highest effects on fruit numbers (73 fruits), yield per plant (5 kg) and yield per area (10 kg/m2) in tomato. in cucumber, the highest fruit numbers (41 fruits) and yield per plant (6.4 kg/m2) was observed in flowering stage. the highest fruit number (6.7 fruits), mean fruit weight (447.3 g fruit-1) and yield per plants (3 kg/plant) was observed in eggplant with application of phenyl-phethalamate before flowering as well as 2 weeks later. in cabbage, foliar spraying at transplanting time, 2 and 4 weeks later, produced the largest heads (2.4 kg head -1) and the highest plant total weight (3.68 kg f.w.).