The effect of duration and condition of incubation, weight of mother corms and photoperiod on corm and shoot characteristics of saffron plant (Crocus sativus L.)

Although botanical characteristics of saffron are well documented in the literature, there is little evidence on physiological aspects of this plant. Four separate studies were conducted to evaluate effects of duration and conditions of incubation period, weight of mother corm and different light / temperature regimes on aerial and corm criteria of saffron. Results showed that at the end of growth period, reduction in mother corm was more pronounced under natural condition compared with the growth chamber conditions (4.2g vs. 2.7g /corm). Incubation period of 120 days compared with 60 days caused more reduction in corm size. A combination of 120 days incubation in growth chamber and bigger size of corms caused more rapid emergence of aerial parts and an increase in leaf area. Corm size had no effect on length of planting to emergence of aerial part, leaf area and number of active buds on corms but incubation of corms in growth chamber promoted emergence of aerial parts significantly. Length of planting to emergences of aerial parts was longer with 120 days compared with 60 days incubation. However, with application of water to corms this event was shorter. Light / temperature regimes had a significant effect on length of emergence of aerial parts, root and aerial dry mater, leaf area and number of active buds on corms and increasing light period for 6.5 to 16 hours increased all these parameters. When corms were exposed to light regimes of 16/8 (light and dark) 33% of corms initiated flowering compared with 75% for corms exposed to natural conditions. Corms exposed to light regimes of 6.5/5.5 did not initiated flowering.