Allelopathic Effects of White Top (Cardaria draba L.) on Sorghum (Sorghum bicolor L.) Germination

This study was carried out to determine the effects of aqueous extracts of (cardaria draba L.) organs (root, stem, leaf and their mixture) on germination of sorghum. The experiment was laid out as a completely randomized design with factorial arrangement and in four replications in research lab of agricultural college at Birjand University in 2010. The treatments included aqueous extracts of root, stem, leaf and their mixture at concentration of zero (check), 10, 20, 40 and 80 percent. According to the results, extracts of different tissuess on germination and root length could be 5% on level, and the germination rate and number of lateral roots was significantly different at 1% percent. The effect of white top extract concentration on all measured traits were significant at 1%. Infact, different organs and concentrations of white top affects considerably prevential on germination of sorghum seeds. Similar results were observed in concentration of 80% by volume, So that the largest percentage of decline in sorghum seed germination (22.5%) were related to the recent treatment.