Weed Seed Germination Under Simulated Drought

Seeds of five crop and 17 weed species were germi- nated with 0, 3, 6, and 10-bar water solutions of polyethylene glycol to simulate drought. With simulated drought, most weed species germinated better than soybeans (Glycine max L. 'Hampton 266A') but were not equal to pearlmillet (Pennise- turn typhoides (Burm.) Stapf. and C. E. Hubb 'Millex 23') or sorghum-sudangrass (Sorghum bicolor (L.) Moench x S. su- danense (Piper) 'SX-16'). Prickly sida (Sida spinosa L.), sickle- pod (Cassia obtusifolia L.), and Ipomoea lacunosa L. were the most tolerant weed species to simulated drought. Four species were intermediate in tolerance and four species germinated poorly under simulated drought. Hemp sesbania (Sesbania exaltata (Raf.) Cory) was the least tolerant and was similar to soybean.