Variation of weed-suppressing potential of Vietnamese rice cultivars against barnyardgrass (Echinochloa crus-galli) in laboratory, greenhouse and field screenings

Abstract A total of 73 different varietal groups and cultivars of Vietnamese rice (Oryza sativa L.) were evaluated for the allelopathic potential on barnyardgrass (Echinochloa crus-galli) in laboratory, greenhouse and field screenings. In a bioassay, Y1, U17, Nep Thom and Lua Huong, cultivars showed the highest weed-suppressing ability against the length of shoot and root of barnyardgrass. Y-1, Nhi Uu and Khau Van exerted significant inhibitory effects in greenhouse screening. In the field study, Phuc Tien obtained the highest weed-suppressing potential. The allelopathic activity of Vietnamese rice showed cultivar-dependence and varietal group-dependence, of which hybrid group cultivars (H) showed the highest inhibition, followed by the local non-sticky cultivars (LNS), foreign (F), traditional sticky (TS), and traditional upland sticky (TUS), while the least were the local upland non-sticky (LUNS) cultivars. The inhibition exerted in both bioassay and greenhouse was lower than the observed weed suppressi...