Drought stress can play an important role in limiting crop productivity and disturbing different stages of plant growth especially at seed germination in arid and semiarid regions. Breeding for drought tolerance at germination stage can enhance the number of seedlings, resulting in a higher yield of grain in rapeseed. In this research 32 cultivars of rapeseed were evaluated for drought tolerance induced by Polyethylene glycol at germination stage according to factorial experiment, based on a completely randomized design with four replications. Osmotic drought stress treatments in four levels including distilled water, -5 and –10 bar was created according a preliminary test. Results indicated high significant differences among cultivars, drought stress levels and their interactions. Drought stress not only decreased germination percentage but also reduced seedling growth. Based on principal component analysis, the first two components named germination potential and seedling growth. Distribution of genotypes based on biplot analysis showed that there is enough genetic variation among cultivars for germination characteristics associated under drought tolerance. Cultivars Likord and Okapi were identified as the most tolerant genotypes. Result indicated that principal component analysis can be used as a useful technique for screening drought tolerant genotypes and identifying relationships between indices.

Keywords: Rapeseed, Drought stress, Seed germination, Variation, Seedling growth.

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