Abstract
The present study was to identify the communities ofB. tournefortiiGouan in Al-Jouf areas in northern Saudi Arabia, to determine soil factors controlling its genetic variability and its allelopathic control. The plant communities dominated byB. tournefortiiwere investigated in fifteen localities. A collection of fifteen Saudi ArabianB. tournefortiipopulations was evaluated using five morphological traits. Analysis of variance and correlation coefficient were performed based on R software package. Soils representing each community were analyzed using eleven physico-chemical parameters. The allelopathic effects ofPortulaca oleraceaandPulicaria undulataand their mixtures on germination, seedling root and shoot growth ofB. tournefortiiwere investigated. The dendrogram based on trait variation using UPGMA method, shows genetic difference between the studied populations. Genetic variability analysis showed a important variability of number of seeds per plant (cv = 19.522) and number of pods per plant (cv = 11.663). The water extracts ofPortulaca oleraceaandPulicaria undulatacould be applied at a concentration of 10 g/L for the management of this species.