Distribution of K, Ca, Mn, and Zn in Different Parts of Spike and Spikelet in Wheat Cultivars

Little information is known about nutrient distribution within different parts of spike of wheat, whereas this information is very important for increasing grain yield without negative effect on quality of grain. In this research, the distribution of two macronutrients (K and Ca) and two micronutrients (Mn and Zn) were investigated during grain filling period in bold and small grains in different parts of spike(P,M,D) in two wheat varieties having large grains (Mahdavi) and small grains (Falat). The research was conducted at the agricultural research farm of College of Agriculture in Islamic Azad University of Saveh during 2007-08 season. Statistical design was split plot and randomized complete block design with three replications. The treatments were three levels of nutrients as the main plot (0, 3 and 4 liter per hectare) and the aforementioned varieties of wheat in the sub plots. Concentrations of the macro- and micronutrients were measured by spectrometer and atomic absorption method, respectively. The results have shown the highest grain weight in the central part of spike as compared to the proximal and distal parts of spike. Number of grains in the central part of spike was more than the two other parts (distal and proximal). There was a positive correlation between grain weight and K, Ca, Mn, and Zn concentration in different parts of the spike. This relation was higher in the central part of spike as compared to the other two parts of spike. Concentration of Zn and Mn decreased during grain filling period. Grain nutrient concentration decreased as distance from the rachis increased. The magnitude of the reduction, however, varied by nutrients. In this study, different varieties did not show any difference in distribution of macro and micro nutrients in rachis as well as rachilla.