Effect of Humic Acid Foliar Application on The Yield and Morphological Traits of Some Safflower Cultivars

The present study was conducted to investigate morphological traits, yield, and oil content of some safflower cultivars as affected by humic acid. 

Factorial experiment was conducted based on randomized complete block design with two factors and three replications at the research field of the University of Kurdistan during 2017 growing season. The first factor was three concentrations of humic acid (0, 2, and 4 per thousand), and the second factor was five safflower cultivars (Isfahan native, Sina, Faraman, Goldasht, and Sofeh). 

The results showed that the highest plant height, capitol number per plant, seed number per capitol, and 1000 seed weight belonged to Faraman cultivar compared to the other cultivars. Humic acid significantly increased morphological attributes, yield components, yield, and oil content. The greatest biological yield, seed yield, and oil yield was obtained from Faraman and 4 per thousand of humic acid. The lowest values of mentioned traits belonged to the Sofeh cultivar. 

The Faraman cultivar as affected by 4 per thousand Soluble acid humic not only produced the greatest values of seed and oil yield but also showed a significant response to the second level of humic acid.