Variation in corm origin of saffron (Crocus sativus L.) based on flower yield and bioactive compounds in petals

In addition to the stigma, other parts of saffron (Crocus sativus L.) flower including petals, as by-products of the saffron production process, contain bioactive and antioxidant compounds that are usually left unused. This experiment was conducted at the research field of Shahid Bahonar University of Kerman, Iran, to increase the productivity of this crop as well as investigate the variation in corm origin in terms of flower yield and bioactive compounds of saffron petals. In this regard, different corms from nine different regions of Iran (Bajestan, Estahban, Ferdows, Gonabad, Natanz, Qaen, Sarayan, Torbate-Heydarieh and Zarand) were evaluated during the three growing seasons of 2015-16, 2016-17 and 2017-18. Based on the results, phenolic compounds ranged from 2.83 to 5.24 mg gallic acid/g dry weight and flavonoid compounds ranged from 0.38 to 1.81 mg quercetin/g dry weight in petals. The results also demonstrated that flower-related traits, bioactive compounds and radical scavenging activity were significantly affected by the growing season, corm origin and their interaction. In all the traits studied (except reducing power ability), corms of different origins showed different responses to the growing season. The highest yield was obtained from the corms of Ferdows in the first and third growing seasons and Bajestan in the second growing season. The corms of Bajestan and Gonabad (the highest phenolic and flavonoid contents) and Estahban (the least phenolic and flavonoid contents) showed, respectively, the highest (216 and 217 mg/L, respectively) and lowest antiradical activity in 2016-17 growing season. The corms of Ferdows, Sarayan, Bajestan, and Gonabad origin based on high yield and bioactive compounds content, Qaen and Estahban due to low bioactive compounds content and antioxidant activity, and Natanz, Torbate-Heydarieh and Zarand with the lowest flower production were grouped into three main clusters according to cluster and principal component analyses.