Effect of foliar application of zinc sulfate at phonological growth stages on yield and yield components of spring safflower cultivars

To evaluate the effect of Zn sulfate foliar application on morphologic and quantitative characteristics of safflower (Carthamus tinctorius L.) cultivars, a field experiment carried out in Ramin Agriculture and Natural Resources University of Khouzestan, Iran, in a Factorial arrangement in a randomized complete block design with four replications, during 2012-2013. Treatments consisted of two spring safflower cultivars (Soffeh and Local of Esfahan) and time of foliar application of zinc sulfate (no spraying, spraying at the stem elongation, branching, flowering and grain filling), were considered. The results indicated that foliar application of zinc sulfate were significant effect on morphologic characteristics, number of head per plant and per square meter, 1000 grain weight, grain yield, biological yield and oil yield. Effect of cultivar on first branch height, number of secondry branch, head diameter, number of head per plant and per squar meter and number of grain per head was significant. Interaction of cultivar and foliar application has significant effect on grain oil contents. The spraying in the stem elongation and branching stage indicated maximum effect on morphologic characteristics. The maximum grain yield and yield components and oil yield were obtained in spraying in the branching stage. The spraying in the stem elongation stage increased biological yield. The highest amount of grain oil content was obtained in cultivar of Soffeh with spraying in the stem elongation stage. The experiment result indicated that local cultivar of Esfahan and spraying in the branching stage, had best morphological traits and yield of safflower in the climatic conditions of the experimental area.