Effect of corm size and corm soaking in polyamines on yield and vegetative and qualitative traits of saffron

To investigate the effect of polyamines on vegetative and biochemical traits of Crocus sativus L., an experiment was conducted as factorial in a randomized complete block design with three replications in 2015-2016 in Training Field of Tarbiat Modares University with three sizes of corms (3-5, 5-7 and 7-10 g) and five concentrations of polyamines (zero in control, zero in distilled water, spermidine 0.5 and 1 , putrescine 0.5 and 1 ) as the treatments. Results showed that plants treated with putrescine 0.5 and spermidine 1 mM had the highest germination percentage (96.56 percent) and the highest number of lateral sprouts (average number of 8.33), respectively. The length and weight of the leaves were negatively affected by polyamine treatment. The highest chlorophyll content and corm yield were observed in plants treated with Putrescine 0.5 mM and 1 mM, respectively. The content of starch and soluble carbohydrates in dormant corms at the end of growing season were not affected by polyamines significantly; however, total phenolic and flavonoid content in these corms were respectively decreased and increased as a result of applying polyamines. Having no significant effect on stigma dry weight and picrocrocin content, polyamine treatment increased the number of flowers and crocin content in small corms. It is concluded that to obtain better vegetative and biochemical traits of saffron, corms more than 7 g, treated with putrescine, should be used.