Effect of Foliar Application of Chelate Iron in Common and Nanoparticles Forms on Yield and Yield Components of Cumin (Cuminum cyminum L.) under Drought Stress Conditions

Introduction Cumin is a member of Apiaceae family and annual plant which is widely cultivated in arid and semi-arid zone. Iran is one of the main producers of this plant. Water deficit is the major limiting factor in crops production. Proper nutrition management under stress conditions could partly help the plant to tolerate different stresses. Various studies were carried out to understand the effect of nanoparticles on the growth of plants. For example, Hong et al. (2005) and Yang et al. (2006) reported that a proper concentration of nano-TiO2 was found to improve the growth of spinach by promoting photosynthesis and nitrogen metabolism. Iran a country with arid and semi-arid climate, always face water deficiency. Thus the aim of this research was investigate the effect of foliar application of chelate iron in common and nanoparticles forms on yield and yield components of cumin (Cuminum cyminum L.) under drought stress conditions. Materials and Methods A field experiment was conducted as a split plot in complete randomized block design with three replications in Esfahan city, during the growing season of 2015-2016. Treatments were included three irrigation intervals (5, 10 and 15 days) as main plots and Fe foliar application in four levels (control, 2 g L-1 iron chelate, 2 g L-1 Nano-iron chelate, 4 g L-1 iron chelate, 4 g L-1 nano-iron chelate). Foliar application of Fe chelate on leaves was done two times at before and after flowering stage. The plots were 16 m2 with 4 sowing rows, 4 m long. Seeds were placed at 2 to 4 cm depth in each row. All data collected were subjected of analysis of variance (ANOVA) using MSTATC software. Significant differences between means refer to the probability level of 0.05 by LSD test. Results and Discussion The results indicated that drought stress decreased the investigated traits significantly but the effect of irrigation by 15 days interval was more than 10 days. Plots which irrigated by 15 days interval showed minimum height, number of umbels, number of grain per umbel, 1000-grain weight, biological and grain yield. Abd El-Kader et al, (2010) reported that decrease in fruit and seed yield of okra occurred by increasing the irrigation interval. Also the results suggested that spraying application of Fe chelate in common and Nano forms increased the yield and yield components on cumin in comparison to control. The maximum and minimum height by 27 and 21.3 cm was observed in 4 g.L-1 Nano-iron chelate and control (no spraying) treatments respectively. The mean comparison of interaction effects showed that the minimum 1000-grain weight (1.5 g), grain (610.7 kg ha-1) and biological yield (1767 kg ha-1) was obtained in control × irrigation by 15 days interval. The maximum effects of iron chelate on increasing of traits was found by foliar application of 4 grams per liter Nano iron chelate. Liu et al, (2005) reported that Nano-Fe2O3 promoted the growth and photosynthesis of peanut. Sheykhbaglou et al, (2010) showed that application of Nano-iron oxide particles increased soybean yield. Reduction of particle size results in increased number of particles per unit of weight and specific surface area of a fertilizer that should increase contact of fertilizer with plant leading to increase in nutrient uptake. Nano-particles have high reactivity because of more specific surface area, more density of reactive areas, or increased reactivity of these areas on the particle surfaces. Below 100 nm Nano-particles could make plants use fertilizer more efficiently, reduced pollution and more environmentally friendly, dissolve in water more effectively thus increase their activities. Conclusions Overall, the results showed that water deficit decreased the yield and yield components of cumin but foliar application of Fe chelate in Nano and common forms increased investigated traits. The results indicated that no significant difference was observed in most of the traits between the foliar application of 2 g.L-1 Nano iron chelate and 4 g.L-1 iron chelate. Based on our results can be concluded that foliar application Fe chelate specially Nano-form can reduced stress effects on plant and finally caused increase yield and yield components