Abstract: A two-year field study was conducted to determine the effects of different seed quality on plant stand and seed yield. Mixing dead seeds ranging from 5 to 50% into high quality seeds, eleven different seed qualities were created. The study was planted in the experimental field of Cukurova University on a silt loam soil in a Randomized Complete Block Design with three replications. Dead seed rate had significant affect on the number of plant per hectare. The highest plant population was obtained from no dead seed added treatment and the lowest was obtained from 50% dead seed added treatment in both years. Pod number and seed number per plant increased with the decreasing number of plant per hectare. Seed yield was positively correlated with seed quality and number of plant per hectare. The highest seed yields were obtained from 10% dead seed added treatments with the plant densities of 128900 and 127864 ha-1 in 2003 and 2003, respectively. Seed yield increased with the increasing plant density upto a maximum level and declined when plant density was increased further. Results showed that use of high quality certified seeds are required to obtain adequate plant number per unit area for maximum yield. It is recommended that certified seed must be used to reduce the risk of stand establishment failure to ensure full seed yield.