Evaluation of Allelopathic Effects of Iranian Rice Cultivars (Oryza sativa L.) on Growth Factors of Barnyard Grass (Echinochloa cruss-galli L.)

In order to investigate the ability of aqueous hull extract of Iranian rice cultivars in controlling barnyard grass germination and seedlings growth, a factorial experiment was carried out at both Laboratory and greenhouse based on RCB (Randomized Complete Blocks) with 3 replication. In this study which was performed in 2010 at Tarbiat Modares University, the effects of 20 rice cultivars hull extract were considered on germination and seedling growth of barnyard grass weed at four concentrations (0, 5, 10 and 15 percent). Lab studies showed that some of the rice cultivars have stimulating effects on barnyard grass growth, while some others have inhibiting effects. Khazar cultivar showed the highest inhibiting effect on germination percentage, germination rate, radicle length, plumule length, radicle and plumule dry weight. Breeded cultivars had higher inhibition effects than natives, while the native cultivars were more stimulating on barnyard grass seed germination. The greenhouse part of study showed that Khazar cultivar causes significant reduction in germination percentage, germination rate, radicle length, radicle and plumule dry weight and whole plant dry weight of barnyard grass. Neda cultivar showed the highest effect in controlling plumule length. The study showed that various rice cultivars have different effects on inhibiting or stimulating the growth factors of barnyard grass.