Corm Enrichment by Foliar Application of Nutrients Improves Saffron Quality

Abstract

Saffron, a member of Iridaceae, is well known as a precious medicinal plant. Saffron yield and quality is influenced by agronomic practice. Previous studies have shown positive effects of application of chemical and organic fertilizers on saffron growth and flowering concluding that saffron crop responses positively to nutrients availability. In order to investigate the effect of nutrient foliar spraying on saffron quality we carried out an experimental trial at Sarayan faculty of agriculture, University of Birjand (Iran) during 2016-18. We evaluate the effect of chemical fertilizer, containing 12% N, 8% P2O5, 4% K2O, 2000 ppm Fe, 1000 ppm Zn, 1000 ppm Mn and 500 ppm Cu, provided by Dalfard company, adopting a randomized complete block design, with three replications. Plant nutritive spraying was done two times during March 2017 and 2018 in order to evaluate its effects on stigma quality of the next foreseen flowering time (November 2018). Effects of foliar application of nutrients were significant and positive on stigma color and on crocin, picrocrocin and safranal. All stigma quality parameters showed a significant improvement, particularly, its color and aroma which represent two key traits of saffron added value chains. The foliar treatments significantly increased the value of the a* and Chroma color parameters and enhanced the content of crocin and picrococin confirming this growing technique can be considered as an appropriate strategy for restoring corm growth before the spring dormancy, by increasing its reserves. Therefore, foliar application of nutrients during vegetative growth of saffron, will support the stigma quality during the next flowering season.