Abstract
•Foliar application of chitosan at flowering stage enhanced chamomile flower number, weight per plant and yield per fed.•D,L β aminobutyric acid at 20 or 40 ppm enhanced volatile oil yield beside increasing chamazulene content.•Application of chitosan and BABA at the rate of 40 ppm is recommended for German chamomile cultivation.
The effect of chitosan and D,L β aminobutyric acid (BABA) at rates of 10, 20 and 40 ppm on the flowering, and chemical characteristics of German chamomile (Matricaria recutita L. cv. Bode-gold) was studied. Chitosan treatments with different concentrations significantly increased flower number per plant, flower head fresh weight, flower head dry weight, and yield of dry flowers per fed in comparison with all other treatments including the control (untreated plants). Plants treated with BABA had bigger flower head diameter compared to the other treatments including the control. The highest concentration of BABA (40 ppm) gave the highest volatile oil content in flowers (2.27 and 2.23 % during both seasons) with increasing rates of 32.59 and 29.59 % over that of the control during both seasons, respectively. Chitosan at 40 ppm followed by BABA at 40 ppm exhibited a significant increase in oil yield per fed comparing to the control with no significant differences between both of them ppm during both seasons. The highest percentage of chamazulene as the main active component was recorded in the volatile oil extracted from chamomile plants treated with BABA at 20 ppm. This investigation suggests further studies on using the foliar application of chitosan at a rate of 40 ppm to increase the quality of chamomile flower parameters and BABA at a rate of 40 ppm to improve the percentage and yield of volatile oil.