Effect of irrigation water salinity, manure application and planting method on qualitative compounds of saffron (Crocus sativus L.)

Abstract

The objective of the present study is to investigate the effects of irrigation water salinity,cow manure levels and different planting methods on saffron quality compounds includingcrocin (coloring strength), picrocrocin (bitterness) and safranal (aromatic strength). A split-splitplot arrangement was conducted in complete randomized block design with irrigation watersalinity levels (0.45 (fresh water, S1), 1.0 (S2), 2.0 (S3) and 3.0 (S4) dS m-1) as the main plot,cow manure levels (30 (F1) and 60 (F2) Mg ha-1) as the sub plot and planting method (basin (P1)and in-furrow (P2)) as the sub-sub plot in three replications. Results showed that the saffroncoloring strength, bitterness and aromatic strength in higher salinity level decreased by 9, 1 3and 18% in comparison with the lowest salinity level, respectively. However, saffron(stile/stigmas) yield declined significantly as about 42% by increasing water salinity to highestlevel. The saffron crocin and picrocrocin concentration for the in-furrow planting method weresignificantly higher than the basin planting method by about 4 and 8%, respectively. Higherapplication rate of cow manure (60 Mg ha-1) did not promote the saffron quality compounds.Furthermore, planting methods showed no significant effect on saffron aromatic strength.Correlation analysis indicated that saffron quality compounds showed negative relationship withleaf calcium, sodium and chloride and positive relationship with leaf phosphorus, nitrogen andpotassium at 0.01 and 0.05 significant levels, Furthermore, a positive correlation between crocinand picrocrocin and saffron yield components (leaf dry matter, corm, flower and saffron yields)was observed; however, there was no significant correlation between safranal and yieldcomponents. Generally, the saffron quality compounds variations were concurrent with thesaffron quantity variations.