The influence of deficit irrigation, amino acids (AA) treatments and their
combinations on growth, yield and volatile oil content of (Rosmarinus officinalis L.) plant
was investigated. Three irrigation treatments were applied in this study. The first treatment
was 100% of the field capacity (FC) as a control. The second and third treatments were
received 80% and 60% of the FC, respectively as deficit irrigation treatments. AA was
applied at 0, 1, 2 and 4 ml L-1. Deficit irrigation treatments significantly reduced the growth
parameters, herb and oil yields, relative water content (RWC), chlorophyll and N, P and K
percentages compared to the control. However, deficit irrigation increased the volatile oil
percentage and total carbohydrates. Increasing AA level significantly increased all the
previous parameters and the best results were obtained by applying the highest AA level (4
ml L-1). The treatment of 100% FC combined with 4 ml L-1AA was the most effective
treatment. The GC results of volatile oil showed that the main components were α-pinine,
camphine, 1,8-cineol, verbinone and borneol and were affected by irrigation and AA
treatments. Results indicated that there is a high potential for saving water by using amino
acids with lower irrigation levels in rosemary production since AA partially alleviated the
negative effects of deficit irrigation.