Effect of secondary dormancy induction on seedling emergence of canola genotypes

The purpose of this study was to quantification the effect of secondary dormancy inducing on emergence rapeseed using Chapman-Richards model under field conditions. This experiment was carried out using 20 rapeseed genotypes cultivated in Iran under field conditions. Seeds were tested for secondary dormancy according to the Hohenheim standard dormancy test. Seedling emergence trial was carried out using a randomized complete block as a factorial arrangement with four replications in a research farm of Abourahian Campus, University of Tehran for 122 days. Emerged seedlings were removed after counting. The results of this study showed that both genotype and drought stress factors are effective on seedling emergence percentage and rate of rapeseed under field conditions. However, potential secondary dormancy inducing was different among the cultivars, and in Karaj2, H50 and SLM046 genotypes emergence rate before inducing secondary dormancy was 0.407, 0.143 and 0.355 which increased to 0.411, 0.228 and 0.364 after inducing secondary dormancy, respectively. the results of the mean comparison showed that the maximum percentage of emergence in nondormant seed was related to Ahmadi cultivar, but this cultivar was not significantly different with other varieties of Hayola, Moghan, SLM046, RGS003, Opera and Karaj. When secondary dormany induced to seeds, Ahmadi cultivar had the highest percentage of emergence and the lowest percentage of emergence after dormancy inducing was related to Talayeh cultivar.