Allelopathic Effect of Saffron (Crocus Sativus L.) on Germination and Seedling Growth of Four Sorghum (Sorghum Bicolor L.) Cultivars

Saffron (crocus sativus L.) is an important cash crop in Iran that propagates by its corms. Usually, rate yield reduced 5-6 years after primary plantation. For this reason, farmers begin to recultivate new corms or intercropped cultivation. Sorghum (sorghum bicolor L.) could be introduce as a suitable candidate for intercropped cultivation. Therefore, in our research we attempt to investigate allelopatic effects of leaf, corm and petal extracts of saffron on seed germination and early growth stage of four sorghum cultivars. Aqueous and alcoholic extract were prepared from dry powdered of saffron organs at 0-4% and 0-1% (w/v) concentrations, respectively. Then sterile seeds were exposed to these extracts. Experiments were designed in a randomized complete block as a factorial experiment with 4 replicates. The results showed that rate and percent of germination, length of root, shoot and leaf, fresh and dry weights of seedling reduced in 4 sorghum cultivars by both extracts. Root growth was significantly decreased in comparison to shoot and leaf. Also, measurement of dry weight revealed that the accumulation of biomass was less affected in shoot. In spite of less growth of root, water content of seedling did not show obvious reduction. It is suggested that root cells were surmounted to stress by osmotic regulation and dilution of toxic compounds. Also, result showed that leaf and petal extracts were more effective than corm tissue; and among 4 studied cultivars Kimia and Payam were resistant to petal and corm extracts but Spidfid and Sugargraz were more resistant to leaf extract.