Two filed experiments were conducted on dill (Anethum graveolens L.) fertilized by different nitrogen and phosphorus fertilizers rates (0.0, 75 and 100 % of recommended rate) and sprayed by different Ltryptophan (Trp) concentrations (0, 50, 100 and 150 ppm) during 2017/2018 and 2018/2019 seasons at Agric.
Res. Farm (Ghazala Farm), Fac. Agric., Zagazig Univ., Egypt, to study the effect of the two factors and their combination treatments on growth, yield components and volatile oil production as well as some chemical constituents of dill. The experimental design was a split-plot arranged in a randomized complete blocks with three replications. The main plots were assigned for three fertilization rate and sub plot were devoted for four tryptophan concentrations. The obtained results referred to that plant height, number of branches per plant and
total dry weight significantly increased by using each NP fertilizers at 100% RR or tryptophan acid at 150 ppm concentration as well as in combination compared to control. Yield components (fruit yield/plant and/feddan)
and volatile oil production (volatile oil yield/plant and/feddan) were increased gradually by increased NP fertilizers rate during both seasons. The best combination treatment in this connection was 100% RR of NP
fertilizers combined with 150 ppm of Trp acid compared to the other ones under study. The same trend were achieved regard chemical constituents (total chlorophyll a+b, total carbohydrates, total nitrogen percentage and
total phosphorus percentage) compared to control.