The effect of seed deterioration on seedling emergence and grain yield of winter rapeseed cultivars

The effect of seed deterioration on seed emergence and seed yield of two oilseed rape cultivars (Licord and Okapi) was investigated in a factorial experimentation based on an RCB design with 3 replications in 2008 at the Research Farm of the Tabriz University, Iran. A sub-sample of seeds of each cultivar was kept as control (V1 with 98% viability) and two other sub-samples of Licord and Okapi with about 15.5% moisture content were artificially deteriorated at 40°C for 9 and 12 days, and for 7 and 10 days, respectively, (V2 and V3 with 85% and 71% viabilities, respectively). The highest percentage of seedlingemergence was obtained for the high quality seed lot and decreased with decreasing seed lot viability. Although grain yield per plant for plants from deteriorated seed lots (V2 and V3) were higher than those from high-viability seed lot (V1), but these advantages in individual plant performance were not sufficient to compensate for low stand establishment as indicated by 26.18% and 49.75% loss in grain yield per unit area for plants from V2 and V3 seed lots, respectively. Consequently, grain yield per unit area significantly improved with increasing seed vigor and viability of oil seed rape cultivar.