Abstract

Argemone ochroleuca Sweet, allelochemicals are reported to potentially suppress crop growth even though empirical evidence of this interaction is scant. This study was conducted during 2020 at the University of Mpumalanga_ to determine the effects of A. ochroleuca residues on common beans germination and early-growth under laboratory and greenhouse conditions, respectively. Germination test, common bean seeds were exposed to eleven A. orchrolueca shoot and root extract concentration of 0 to 100 g/L, while eight powder levels of 0 to 14 g were used to test effects of the same plant parts on early-growth. Germination percentages (GP), mean germination time (MGT), germination speed (GS), mean daily germination (MDG), plumule and radicle length were computed over 7-day period. As extract concentrations increased, GP, MGT, GS, MDG, plumule and radicle lengths decreased by 30–54, 41–55, 37–55, 35–46, 41–82 and 46–79%, respectively. Thirty-days after the first emergence, A. ochroleuca concentrations decreased plant height, stem diameter and dry shoot mass by 71, 75 and 75%, respectively. Shoot extracts were more suppressive to germination and early-growth of beans than root extracts. In conclusion, A. ochroleuca extracts had concentration-dependent inhibitory effects on germination and growth variables of A. ochroleuca, shoot extracts exhibiting higher allelopathic effects compared to root extracts.