Effects of Different Water Supply and Corm Planting Density on Crocin, Picrocrocin and Safranal, Nitrogen Uptake and Water Use Efficiency of Saffron Grown in Semi-Arid Region

Alireza Koocheki,Seyyed Mohammad Seyyedi

doi:10.15835/nsb839855

Abstract

Saffron’s color, taste and odor result from the chemicals crocin, picrocrocin and safranal, respectively. Hence, in addition to quantitative yield, secondary metabolites content are known as crucial factors for a successful saffron production. Moreover, enhancing resources efficiency, especially water and nitrogen, is becoming increasingly important for agricultural improvement in arid and semi-arid regions. Thus, the effects of irrigation levels and corm planting on crocin, picrocrocin and safranal content, water use efficiency (WUE) as well as nitrogen use efficiency (NUE) of saffron were investigated as a two-year field experiment based on a randomized complete block design arranged in split-plot with three replicates. The irrigation levels (100, 75 and 50% of saffron water requirement) and corm planting pattern (50, 100, 200 and 300 corms m-2) were allocated to main and sub-plots, respectively. Based on the results, crocin and picrocrocin content increased with decreasing irrigation levels. The highest WUES (WUE based on dry stigma yield) was obtained when 50% of saffron water requirement was supplied. However, the lowest WUEC (WUE based on daughter corms yield) and NUEC (NUE based on daughter corms yield) were obtained when 50% of saffron water requirement was applied. Irrespective of irrigation levels, WUES, WUEC and NUEC increased with increasing the planting density. The results demonstrated that although relatively severe water stress increases WUES and secondary metabolites in saffron stigmas, it could decrease WUEC and NUEC through affecting daughter corm growth.

Highlights

Saffron (Crocus sativus L.) is a sterile geophyte plant growing in arid and semi-arid regions of the world (Sepaskhah and Kamgar-Haghighi, 2009)
Flower quality the effect of irrigation levels on crocin and picrocrocin content was significant, safranal content was not affected by irrigation levels (Table 3)
Crocin and picrocrocin are the most important compounds found in saffron stigmas (Tarantilis et al, 1995; Escribano et al, 1996), so that higher amounts of these compounds leads to an increase in the quality of saffron (D’Auria et al, 2004; Srivastava et al, 2010; Koocheki et al, 2016)

Summary

Introduction

Saffron (Crocus sativus L.) is a sterile geophyte plant growing in arid and semi-arid regions of the world (Sepaskhah and Kamgar-Haghighi, 2009). According to saffron’s irrigation schedule, an optimal irrigation schedule consists of five to six irrigation rounds (Koocheki et al, 2014; 2016) These irrigation rounds are usually performed in mid-summer (for flowering induction), in early October (for flowering acceleration), in November (after flower picking and leaves appearance), in December (after winter weeding), in March and in April (supplementary irrigation for optimum daughter corm growth). In some arid and semi-arid regions, saffron fields are irrigated only once (in October), mainly due to water shortage, causing a significant reduction in flower and corm yields (Kafi et al., 2002; Koocheki et al, 2014). In spite of being a crop compatible with arid and semi-arid regions, with low water requirements

Methods

Results

Conclusion