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

This study was done to evaluate the allelopathic abilities of 40-Sri Lankan improved rice varieties to control the Echinochloa crus-galli L. (Barnyard grass-BYG) using rice/ BYG mixed cultures in trays, Double Pot Technique test and a field experiment. In tray experiment, significant inhibition in plant height and dry weight were observed in rice/ BYG mixed-cultures than monoculture controls. Varieties which showed highest and lowest inhibition (%) in tray experiment were further tested in Double Pot Technique test and later in field experiment. Among the 40 rice varieties, Ld 365, Ld 368, Ld 408 and Ld 356 proved most inhibitory to BYG growth and 40% inhibition in BYG dry matter accumulation. Hence, these varieties can be used for further allelopathic studies.