Study on Effect of size on characteristics of germination and emergence of different wheat cultivars (Triticum aestivum L.) certified seed in laboratory and field in karaj

From among producing factors, seed as the first consumer store, plays an important role in the transfer of genetic characters and increase of qualitative and quantitive in production. out of growth stages of plants, seed germination and emergence stages are important and will have attentive role on later growth stages of plant in filed. In order to investigate the impacts of seed size on characteristics of germination and emergence of different wheat genotypes (Triticum aestivum L.), This experiment was conducted in, 2008-2009 , at seed and plant certification and regesteration institute, karaj. Iran. the experiment factors were seed size with five levels (2-2,2, 2-2,5-2, 5-2, 8, 2, 8-3, 3 mm ) and Mahdavi, Pishtaz and bahar wheat genotypes. In laboratory, various treatments was planted with randomized complete block design with 3 replicates. germination percentage, speed of germination, Seedling-length, radicle-length, plumule-length, radicle dry weight, plumule dry weight and seedling dry weight were measured. Factoriel design in the shape of randomized complete block with 3 replicates was conducted at Institute Research Farm. Seedling emergence(%), green weight of 100 seedling (gram) and dry weight of 100 seedling (gram) in each plot were recorded about 14 days after emergence( 1 month after planting). Seed size had significant impact on germination rate, radicle dry weight, plumule dry weight and seedling dry weight, Seedling emergence(%), green weight of 100 seedling and dry weight of 100 seedling.Speed of germination showed significant decrease with increasing seed size. The other traits showed significant increase with increasing seed size. Seedling emergence(%) decreased in largest size. Assessment of treatments in experiment showed seed size no had significant impact on germination percentage, but it changes seedling emergence, wheras emergence percentage of seeds with 2-2, 2 size was significantly less than compared to other sizes. genotype had significant impact on characteristics of germination and emergence with the expception of germination percentage, speed of germination, Seedling emergence(%). preformance of mahdavi genotype in length and seedling dry weight(in laboratory) and dry weight of 100 seedlings (in field) is due to more nutrient saved in seed of this genotype. significant interaction was observed for radicle-length, plumule-length, seedling dry weight, green weight of 100 seedling and dry weight of 100 seedling. This subject is due to that various genotypes don t have same reaction with variation in seed size in this characters.