investigation of irrigation regime and sowing date effect on seed vigor of rapeseed cultivars with accelerated ageing test

this study was carried out to evaluate the association between laboratory seed characteristics and seedling emergence of canola cultivars that it's were produced under different irrigation regime and planting date. the treatments were included two planting date and two levels of irrigation (main factors) and seeds of five canola cultivars (sub factor) which in first year (2006-2007) had been cultivated in a factorial split plot design based on rcbd at experimental field of seed and plant improvement institute. in second year, the experiment was conducted in research field and laboratory of agronomy and plant breeding department at college of aboureyhan -university of tehran- during spring 2008. the analysis of variance results indicated that planting date and irrigation regime had no significant effect on measured traits under field experiment, whereas, in laboratory experiment, the effect of planting date and irrigation regime were significant on radical length (rl) and shoot length (sl), alone. based on the laboratory results, the sarigol cultivar due to higher mean daily germination (mdg), radical length (rl), lower mean time to germination (mtg) and daily germination speed (dgs) had the highest vigor seed. the results of correlation showed that there is the positive and significant correlation (0.59**) between final emergence percentage and rl in laboratory experiment (accelerated ageing test), therefore, accelerated ageing test can be used for predication of percentage of emerging plants in the field.