This experiment was conducted at the Experimental Research Station, Agric. College, Baghdad, during 2015-2016, growing to study the effect of three planting dates (15/9 , 15/10 and 15/11) as a main plots, and three foliar spray rates of salicylic acid (50,100 and 200) mg.L-1 in addition to control, on growth of burdock plants (Arctium lappa L.) and their content of quercetin and arctiin compounds . The results of study showed that plants of the first planting date (15/9) significantly increased plant height , leaf area, dry weight of vegetative growth, dry weight of roots and content of arctiin (0.410 mg.plant-1 dry wt.) , as compared to other planting dates. Third planting date (15/11) significantly exceeded others in roots content of quercetin (6.428 mg.plant-1 dry wt.). 100mg.l-1 salicylic acid gave the highest plant height, leaf area, dry weight of vegetative growth and dry weight of roots, and on roots content of quercetin (6.366 mg.plant-1 dry wt.),however, 200mg.l-1 gave the highest value of arctiin (0.432 mg.plant-1 dry wt. Dual interaction showed sinificancies only in root contents of quercetin and arctiin.
Qasim A. S. Al-Zyadi, Agric. College, Al-Muthanna Univ.*
Sajid O. Mohammad , Agric. College, Baghdad Univ