Response of Some Bread Wheat Cultivars to Foliar Application of Zn and Fe Different Forms in Two Locations with Different Soil Properties

IntroductionZinc (Zn) and iron (Fe) are essential mineral nutrients for plant and human growth, and dietary Zn and Fe deficiencies are a worldwide nutritional problem. The Recommended Dietary Allowance (RDA) of Zn and Fe are 15 mg and 10 mg per day for human, respectively. However, micronutrient deficiencies affect more than half of the world’s population, especially women and preschool children. Iron is one of the most important micronutrients, and approximately two billion people suffer from iron deficiency worldwide. Zinc deficiency is also considered to be quite common and affects newborn, children, pregnant women and elderly. Micronutrient malnutrition in human in developing countries is derived from deficiencies of these elements in staple food. It is believed that increasing the micronutrient concentrations in these crops could increase the dietary intake of these elements in these regions significantly. More than 80% of arable soils in Iran are zinc-deficient with an average yield depression of around 50%. It is, therefore, highly important to develop cost-effective and quick solutions to the Zn and Fe deficiency problem.
Materials and MethodsIn order to evaluate the effect of foliar application of zinc and iron different forms on yield components, phonological and morphological traits and grain yield of some wheat cultivars in two locations with different physico-chemical soil properties, two experiments in factorial arranged in randomized complete block design with three replications conducted during 2015-16 cropping season. Experimental treatments were included: wheat cultivars Roshan, Roshan Back cross (old cultivars), Bam and Ofogh (new cultivars), zinc application in three levels of foliar application of water (control), zinc sulfate and chelated zinc and iron application in three levels of foliar application of water (control), iron sulfate and chelated iron (equivalent to 2.5 kg ha-1). The first experiment was conducted at the Research Farm of Birjand University located in Amirabad region which the soil texture was sandy clay loam, with 8.1 pH, 0.15% organic matter, 30 ppm available P and 184 ppm available K. The second experiment was conducted at the South Khorasan Agricultural and Natural Resources Research and Education Center located in Mohammadieh region which the soil texture was loam, with 7.6 pH, 0.54% organic matter, 30 ppm available P and 140 ppm available K. At the end of growth stage wheat traits included days to heading, days to physiological maturity, grain filing period, plant height, spike length, peduncle length, number of grain per spike, 1000 grains weight, grain yield, biomass and harvest index were measured. Data analyses were performed using two-way analysis of variance (ANOVA) with SAS 9.1. Means of treatments were compared between locations, cultivars and foliar application of zinc and iron according to protected Least Significance Differences (LSD) test at the 5% level.
Results and DiscussionResults showed that location had a significant effect on all traits except for number of grains per spike. Grain yield and yield components were higher in soil of Mohammadieh against Amirabad. Investigated cultivars also were significantly different in all traits but days to heading and biomass. The higher number of grain per spike, grain yield and harvest index and relatively lower 1000 grains weight were related to new wheat cultivars. New cultivars also possessed less height and peduncle length and more grain filling period and spike length. Zinc foliar application significantly increased plant height, spike length, number of grain per spike, 1000 grains weight, grain yield and biomass but no significant effects were observed on days to heading and maturity, grain filing period, peduncle length and harvest index. Zinc sulfate treatment increased grain yield and biomass by 9.6 and 8.2 percent and chelated zinc increased these traits by 6.7 and 4.1 percent compared to control treatment, respectively. Iron foliar application significantly increased plant height and grain yield with no significant effects on other measured traits.
ConclusionsFoliar application of zinc and iron can improve growth traits and grain yield; and foliar application of zinc and iron sulfate had better result contrasting these nutrients chelated forms especially in Amirabad region with higher pH and EC. Finally according to the results of this study, cultivating new cultivars of Bam and Ofogh and foliar application of zinc and iron sulfate in similar climate, especially in saline condition, are suggested for wheat production.