The objective of this research was to evaluate the effects of barley and weed control periods on the seed production and growth of Raphanus sativus, the major weed in the experimental area. The experiment was carried out in Botucatu, SP, Brazil. Two checks, with and without the crop, were kept weedy from seeding to harvest. In other eight treatments the crop was kept weed free up to 10, 20, 30, 40, 50, 60, 80 and 100 days after emergence. It were evaluated the number of plants, the dry matter accumulation and the number of fruits and seeds per plant and per m2, the weight of 1.000 seeds and the percent of the seeds in the total dry matter accumulation. Raphanus sativus showed a high reproductive potential, producing 5. 074 seed s/m2 if kept without control in the absence of the crop. Barley reduced the growth and the seed production of R. sativus. To reduce de seed production to values lower than the population density of the R. sativus in the checks, the weed should be controlled up to 30-100 days after crop emergence.
Hordeum vulgare; seed; seeds bank