effects of drought stress and planting dates on seedling emergence, plant growth and seed vigour of produced seeds in canola (brassica napus) cultivars

this research was conducted to evaluate the role of drought stress and planting dates on seeds vigour and seedling growth of produced seeds. the experiment was performed in the research field and seed technology laboratory of the department of agronomy and plant breeding, college of aboureyhan in pakdasht in spring 2008. five canola cultivars including licord, opera, modena, elite, sarigol (in subplots), 2 planting dates including first half of october and first half of november (main plots) and 2 levels of irrigation including normal irrigation and drought stress from stem elongation stage (main plots) which all materials were produced in previous year were used as treatments. time to 50% of seedling emergence and mean daily of seedling emergence were measured. in laboratory, standard germination test was conducted and final germination percentage and germination speed were measured. based on analysis of variance planting date and drought stress had no significant effect on measured characteristics. our results indicated that there is no correlation between final percentage of seedling emergence and standard germination test. therefore, standard germination test can not be used for predication of final emergence percentage in the field. based on the laboratory results, the cultivar sarigol due to higher final germination percentage, mean daily germination and lower daily germination speed had higher seed quality.