Document Type : Research Paper


1 College of Education for Pure Sciences, University of Diyala, Iraq

2 College of Agriculture, University of Diyala, Iraq


A pots experiment was conducted in Baladrooz district, Diyala Governorate, Iraq in autumn season 2020 to study the effect of spraying with rapeseed oil and tryptophan  on vegetative growth characteristics of Periwinkle Catharanthus roseus.A factorial experiment was applied with two factors, spraying of the rapeseed oil and tryptophan in three levels (0, 5 and 10 ml. l-1) and (0, 100 and 200 mg. l-1) respectively. The results show that each of rapeseed oil or tryptophan in improved all studied characteristics, when they were sprayed separately, also the interaction between them was effective, Tryptophan 100 mg. l-1 and rapeseed oil 10 ml. l-1 gave the highest increase in number of vegetative branches 11.12 and the number of leaves 84.68, whereas the tryptophan 100 mg. l-1 and rapeseed oil 5 ml. l-1gave the highest value of leaf area 22.36 cm2, fresh weight of the shoot 28.26 g, dry weight of the shoot 7.23 g and dry weight of the root 2.34 g,the tryptophan 200 mg. l-1 and rapeseed oil 5 ml. l-1gave the highest value of plant height 40.00 cm.


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