The Study of Saffron (Crocus Sativus L.) Replacement Corms Growth in Response to Planting Date, Irrigation Management and Companion Crops

Selection of suitable mother corms is an important factor for achieving optimum yield in saffron. In order to investigate the effect of some agronomic factors on the growth of replacement corms of saffron, an experiment was done at the Faculty of Agriculture, the Ferdowsi University of Mashhad, Iran during 2009-2011. The experimental treatments consisted of planting on the following dates (22 May, 22 July and 22 September, 2009), irrigation management (Irrigation and no irrigation after each planting date and repeating them in the second year in late spring, summer and early autumn irrigations) and companion crops [Persian clover (Trifolium resupinatum), Bitter vetch (Vicia ervilia) (Lathyrus sativus) and control), that were arranged in a split-split plot experiment based on a randomized complete block design with 3 replications. Sampling of replacement corms was done after the second growth cycle of saffron in May, 2011. The results showed that with delay in corm planting from May to September, the number of replacement corms and percentage of corms with contractile root increased by 25 and 33%, respectively. However, the amounts of total weight of replacement corms per clone, mean number of flowering buds per corm, mean number of total buds per corm, mean weight and mean diameter of replacement corms planted in July were 21, 70, 40, 32 and 37% higher than those planted in September, respectively. Irrigation increased the amount of contractile roots and number of replacement corms per clone (12%), but decreased the amount of mean number of flowering buds (19%), mean number of total buds (11%) and mean weight (19%) and diameter (8%) of replacement corms. Moreover, application of companion crops had a partially positive impact on the indices of growth of replacement corms of saffron such as follows: the total weight of replacement of corms per clone (8%), corms to scales weight ratio (14%), number of flowering buds (10%) and mean weight of replacement corm (10%). Overall, mother corm planting during real dormancy, no irrigation after planting and during summer as well as application of associated crops have a positive effect on the mean weight of replacement corms as the main important factor in saffron flowering.