Allelopathic potential of rice (Oryza sativa L.) residues against Echinochloa crus-galli

This bioassay was conducted to examine the allelopathic effects of different parts of rice plants, and the genetic and phenotypic characters of rice varieties, on Echinochloa crus-galli P.Beauv. var. oryzi-cola Ohwi. The average inhibition by the variety Duchungjong on E crus-galli (77.7%) was higher than the inhibition by other varieties. The inhibitory effect on emergence induced by a leaves-plus-straw mixture was extremely high for the Damagung strain (95.9%). Daegudo showed the highest percentage inhibition (93.2%) by hull residues. The leaves-plus-straw mixture and hull residue of Basmati showed the highest percentage inhibition on plant height (75.7% and 66.7%, respectively). The leaves-plus-straw mixture and hull residue of Damagung exhibited the highest percentage inhibition of aboveground dry weight (98% and 97.1%, respectively). The greatest inhibition of aboveground and root dry weight by a hull residue was produced by Kasarwala mundara (95.6% and 94.3%, respectively). In terms of origin, foreign varieties showed a greater percentage inhibition (61%) than domestic varieties (52.4%). Rice varieties with intermediate maturing times showed a greater percentage inhibition (59.3%) than other varieties (early maturing 50.2% and late maturing 56.1%). Coloured hulls showed 55.9% inhibition, whereas colourless hulls showed 65.4% inhibition. Awnless, colourless-awn, and coloured-awn groups did not differ significantly in average inhibition (55.6%, 55%, and 53.5%, respectively). (C) 2003 Elsevier Ltd. All rights reserved.