SummaryCompetitive ability of 48 sorghum [Sorghum bicolor (L.) Moench] hybrids and 41 parental inbred lines was evaluated using (a) germination percentage and germination rate index, (b) emergence percentage and emergence rate index, (c) seedling vigor, (d) rate of root and shoot development, and (e) cation exchange capacity of roots as selection criteria. Average response of sorghum hybrids was superior to parental inbred lines in all selection criteria. Sorghum lines selected for high and low seedling growth characteristics in laboratory and greenhouse studies showed corresponding competitive advantages over weeds in field studies. Competitive advantage of sorghum over weeds was largely due to rapid germination, emergence, and root and shoot growth during the early stages of sorghum development.