Study on improvement possibility of germination traits and physical purity of Canola (Brassica napus L.) seed by appropriate conditioning application

According to the effect of seed size on seed quality, this study was conducted in the Seed and Plant Certification and Registration Institute (SPCRI) in 2009-10, based on completely randomized design and with three replications. Studied factors(16 treatments) consisted of two canola cultivars (Okapi and Talaye), four separated seed sizes (1.4, 1.6, 1.8 and 2 mm) and two levels of using and none using of gravity separator tool. Based on the results using of 1.6 mm sieve size accompanied to gravity separator tool is recommended for cleaning these two varieties seed while germination percent and seedling emergence was improved and also higher seed loss percent was attained by using of sieves with 1.8 and 2 mm size. Whatever lower seed loss percent was attained using 1.4 mm sieve size but percentage of seed purity was decreased and also number of weed seeds increased which resulted in rejection at standard seed certification process. So the best treatment was related to the sieve with 1.6 mm size that was standard in the aspect of physical purity and germination percent.