The Effect of Different Levels of Foliar Application of Zinc, Iron, and Manganese Micronutrients on Reproductive Characteristics and Yield of Vitis vinifera Grapes in some Vineyards of Zanjan Province

Introduction Grape (Vitis vinifera L.) is one of the most important economic plants in the world including Iran. One of the most basic effective factors of the growth of fruit trees is knowing their nutrition. Micronutrients are as important as Macronutrients for better growth, yield and quantity in plants. Garden plants suffer from severe zinc deficiency, followed by boron, manganese, iron and molybdenum. Foliar application of fertilizers is a useful tool to increase the nutritional effects of fertilizers or eliminate nutrient deficiencies during the growing season. The aim of this study was to study the nutritional effects of consumption of different compounds of micronutrient fertilizers of zinc chelate, iron and manganese as foliar consumption on the morpho-physiological traits of grape plant.Materials and Methods Field experiments were carried out to evaluate the effects of micronutrients alone and in combination on growth and fruit yield in grape grown at Iran, Zanjan province during 2016-18.  Physical and chemical properties of the soil were evaluated before the experiment. During the two years of the research, no organic or chemical fertilizers were used except for the combination of fertilizer treatments of the relevant design. Treatments consist of foliar consumption of micronutrients fertilizers included two levels of EDDHA-Zn (0.1 and 0.3 %), EDDHA-Fe (0.1 and 0.2 %), and EDDHA-Mn fertilizers (0.1 and 0.2 %) and control levels (0 %) for them. This experiment was implemented in a factorial format based on a randomized complete block design with three replications and repeated for two consecutive ys.  The measured traits consist of Length of the First inflorescence (X1), Number of Inflorescences per Branch (X2), Number of clusters per branch (X3), Number of Clusters per Plant (X4), Weight of a Cluster (X5), Cluster Size (X6), Berry Size (X7), Number of Berries per Cluster (X8), Weight of single Barry, X10: Leaf Area Surface. Leaf Dry Matter (X11), TSS (X12), Sugar Fruit Juice (X13), Fruit Juice Acidity (X14), Fruit Dry Matter (X15), Fruit Firmness (X16), Yield per Plant (X17), Yield per Hectare (X18). The experiment was performed in factorial format with three factors, each at three levels, based on a randomized complete block design with three replications in three locations (g; G) and in each location for two consecutive ys (Y). The analysis of each g was analyzed in the form of factorial experiment design and the effect of location factor was analyzed in the form of factorial-split (time) composite analysis in place. In the statistical model used, time and place factor considered as random and treatment was fixed.Results and Discussion Evaluation of morpho-physiological traits showed that the use of these fertilizers individually or in combination has significant positive effects on all measured traits (18 traits) at different stages of development. The simple effect of the factor of the y was significant only on some of the measured traits and the two and three-way interactions between this factor with the levels of treatment in the majority of traits were not significant; which indicates the probability that the factor of the y has no effect on the measured traits. Based on these results, the treatment combination of Fe 0.2 + Zn 0.3 + Mn 0.2 % EDTA was superior to other combinations, and traits of the number of inflorescence and number of clusters per branch and number of clusters per plant showed the best response than other measured traits. Consumption of micronutrients, especially iron, zinc and manganese, has favorable effects on yield indices, better fruit formation and fruit production per unit area, which affects photosynthetic activities and important metabolic pathways in plants, leading to produce higher amounts of primary metabolites such as higher sugar production in fruit, increase in soluble solids, also increase in growth indices such as leaf area, more yield-related traits such as number of inflorescences and number of spikes per branch and per plant, number and the dimensions of the cube are in clusters. On the other hand, these compounds help to absorb the main nutrients and play an active role in initiating metabolic processes such as cell wall development, respiration, photosynthesis, chlorophyll formation, enzymatic activities, production of growth regulators, and nitrogen fixation and reduction. Accordingly, these compounds were able to show better performance compared to the control level by accelerating the absorption of other nutrients, strengthening biochemical pathways and growth indices.Conclusion According to these results, the application of three fertilizers of zinc, iron and manganese EDTA individually or in combinations of two or three of them, especially at high concentrations simultaneously, is superior in comparison. And the treatment composition of 0.3% zinc + 0.2% iron + 0.2% manganese EDTA and then 0.3% zinc + 0.2% iron + 0.1% manganese EDTA has more significant and positive on measured traits and therefore as fertilizer compositions are recommended in vineyards in the form of leaves.