Effects of Foliar Application of Nutrient Elements on Fruit Set and Quantitative and Qualitative Traits of Keshmeshi Grape Cultivar

To study the effects foliar application of nitrogen, boron and zinc on fruit set and some quatitative and qualitative characteristics of Thampson seedless grape (Keshmeshi cultivar), an experiment was conducted for two years (2001 and 2002) in two vineyards in Uromieh using factorial based on randomized complete block design. Treatments were urea (0, 0.5 and 1%) zinc sulphate (0 and 0.15%), boric acid (0 and 0.13%) and their combinations that applied at seven days before full bloom and fruit set formation. Different quatitative and qualitative characteristics of fruits and fruit set formation were measured in different treatments during the experiment. The results showed that foliar application of nutrient elements had significant effects on fruit set. The highest fruit set percentage was recorded in treatments contained zinc, and the lowest percentage in control and treatments that urea and boron were used alone or in combination. The results of leaf analysis showed also that application of zinc increased zinc contents of leaf tissues up to 68.1 ppm, but appli cation of nitrogen and boron had not any remarable effect on their content in leaves. Nutrient elements application did not have any effect qualitative trails of fruit in the first year, but in the second year zinc containing treatments alone or in combination with urea (0.5%) increased bunch weight significantly. Generally, application of nitrogen, boron and zinc (0.5, 0.15 and 0.15%, respectively) had a positive effect on fruit set, but the role of zinc was much more than the effects of the other two elements.