The Effect of the Method and Stage of Zinc and Iron Micronutrients Application on Bunch Characteristics and Fruit Yield of Yaghouti Grapes

Zinc and iron deficiency in Sistan soils, no use of micro- nutrients fertilizers by gardeners, and low yield are problems facing yaghoti grape production as an earliest- ripening grape cultivar in Iran.This experiment was carried out in the form of factorial based on a randomized complete block design with three replications. The first experimental factor was fertilizing methods included: 1- control (Fm1), 2- foliar spraying of zinc and iron (Fm2), 3- localized placement method of zinc and iron (Fm3) and 4- localized placement method of zinc and iron + foliar spraying of zinc and iron (Fm4) and the second factor was fertilizing stages included 1- bud swelling (Fs1), 2- emergence of bunch (Fs2), 3- verasion (Fs3) and 4- leaf fall (Fs4). The concentration of iron and zinc elements in the fruit in Fm4×Fs3 condition increased by 21.3 and 30.7%, respectively, compared to the control. In the Fm4×Fs2 treatment, bunch length and width, and berry diameter increased by 19, 16.3 and 23% compared to the control, respectively. Also, berry weight, number of berries per bunch, bunch weight, bunchs/vine and fruit yield in the Fm4×Fs1 treatment were increased by 15.7, 18.5, 19.5 and 19%, compared to the control, respectively. The traits measured in this experiment increased each year compared to the previous year. Considering the positive role of zinc and iron elements in improving fruit characteristics and yield, fertilizing Yaghouti grape trees by a combination of localized placement and foliar application methods, with a 19% increase in yield, is recommended.