Abstract
Autotoxicity is injurious effects of a plant on itself via production and released diverse allelochemicals. In order to determine autotoxicity effects of water extract of canola residues on germination traits of two varieties: Elait and Golzard was investigated. Two factorial experiments based a completely randomized design with 3 replications were conducted separately. Treatments were 3 kinds of canola water extract (shoot, root and shoot plus root) and 5 concentrations (0, 25, 50, 75 and 100 percentage) of extracts. Each plot was a Petri-dish with 9 cm diameter and 3 cm depth. At the end of germination, germination inhibition percentage, root and shoot length, root and shoot dry weight and seedling dry weight were determined according to ISTA standards. The results showed water extract of canola had difference autotoxicity effects on germination traits of canola varieties. Increasing concentration of extracts resulted to increased germination inhibition percentage (29.6 and 33.9) and decreased root length (63.3 and 73.8), shoot length (52.2 and 76.6), root dry weight (32.6 and 64.9), shoot dry weight (59.1 and 43.6) and the seedling dry weight (42.1 and 55.5), respectively. Germination traits of variety Golzard was more sensitive at canola extract. The water extract of root than shoot and shoot plus root had the most autotoxicity effects on germination and seedling growth of canola varieties.

Keywords: Autotoxicity, Canola, Germination properties