Effect of Water Potential Levels on Germination and Seedling Growth ‎Stages of Four Canola (Brassica napus L.) Cultivars

In order to evaluate the effects of water potential levels on germination and seedling growth of four canola cultivars, two laboratory experiments were conducted, using a factorial arrangement in a Completely Randomized Design with three replications during 2009. The factors consisted of four cultivars (Hayola, Zarfam, Okapi and Talaye) and four water potential levels (Zero, -0.2, -0.4, and -.06 MPa). In germination experiment results showed that the effects of cultivar, water potential and their interaction on germination percentage and rate; fresh and dry weight and length of radicle and plumule was significant. With reduction of water potential, germination percentage more reduce than germination rate. Okapi and Hayola had maximum and minimum tolerance to reduce of water potential, respectively. In seedling experiment results showed that cultivars, water potential and their interaction had significant effect on length of stem and root, dry weight of stem and root, a/b chlorophyll and leaf proline content. With reduction of water potential, a/b chl. and leaf proline content were increased. In general results showed, Okapi was tolerated cultivar to water stress in germination stage, but at seedling stage, Zarfam was superior genotype, so in different growth stage tolerate to water stress don’t a constant characteristic.