Effects of Extensive Range of Corm Weights on Saffron (Crocus sativus L.) Growth and Flowering

Saffron (Crocus sativus L.) as a spice crop, additive, and flavoring is applied in food industries. Saffron also is applied in medicine as a drug. It has a specific site in Iran exports, so that 90% of saffron production belongs to Iran. In 2016 Iran has been the largest producer of saffron with 336 ton and cultivation area of 105270 ha. Provinces of Khorasan-Razavi and Southern Khorasan are the two main centers of saffron production in Iran. Environmental factors have considerable effects on quantitative and qualitative characters of saffron. Low yield of saffron in traditional farming systems can be due to application of small size corms. Corm size or corm weight is one of the most important factors affecting saffron yield. Research in this regard and finding out a standard size for planting saffron are among research directions for saffron research and development. This experiment was arranged as randomized complete block design (RCBD) with 10 treatments and three replicates at the research farm of college of agriculture, Ferdowsi University of Mashhad (latitude 36 and 16 north and longitude 59 and 36 east and altitude 985m) in cropping year of 2012-2013. Ten weight groups of mother corms were as follows: <2, 2.1-6, 6.1-10, 10.1-12, 12.1-14, 14.1-16, 16.1-18, 18.1-20, 20.1-24 and >24 g as treatments. Land preparation included primary plough, disc and leveler and then to plot the land as 1×1 m with between rows 20 cm as plant density of 50 corms.m-2. Picking saffron flowers occurred in late October as daily basis and corm lifting occurred in June. Measured characters were, number of corms without flowers, number of one flower corms, number of double flower corms, number of three flower corms, four flower corms and higher ones, total number of sister corms, number of sister corms in weight groups of <4, 4-8, 8-12, and >12 g. Data analysis was performed with SAS 9.1 and mean comparisons with duncan’smultiple range test at p ≤0.0 5. Corm weight is very important in flowering capacity of saffron. So, by increasing weight of mother corm, number of flowers may improve. Based on results obtained from variance analysis, number of saffron flowers was affected significantly by weight corms of mother corms (p≤0.01). By increasing corm weight number of saffron flowers increased so that corms less than 2 g produced least flowers and highest number of flowers related to 20.1-24 and 24 g corms with 1250000 and 1300000 flowers.ha-1. These findings have been confirmed another place. Findings of this research showed that the most critical factor affecting saffron flowering is corm weight that is among the few factors affect flowering. We know that there is a positive relationship between corm diameter and corm weight. Some authors apply corm diameter and some other use corm weight but most authors use corm weight. It was concluded that increasing weight of mother corms through increasing number of sister corms caused to increase number of flowers that finally was followed by improvement of dry stigma. Increasing mother corm weight had positive effects on all vegetative and reproductive characters of saffron.