Role of Melatonin Application Date in some Biochemical Characteristics of Sesame Crop Affected by Irrigation Interval

Abstract

A field experiment was conducted during the summer season 2022 at the research station affiliated to the University of Anbar / College of Agriculture in Al-Butha Anbar Governorate, which is located along an eastern length of 43 km and a width of 33 norths. To determine the impact of the date of melatonin addition, the extent of the sesame crop’s response to the irrigation interval, and its impact on the biochemical traits. The experiment was carried out in split plots, according to the RCBD design, with three replications. The main plots included irrigation intervals (5, 9, and 13 days), while the sub plots included melatonin spraying date (30, 40, 50, and 60 days). The results showed that delaying both the irrigation interval and the melatonin spraying date (60 days) and (irrigation interval every 13 days) increased the biochemical characteristics of each antioxidant enzyme’s activity (SOD, CAT, and carotenoids) and indicators of oxidative stress (H2O2, proline, and MDA). The maximum activity for SOD and CAT enzymes (54.95 and 6.78 unit’s ml−1, respectively) and carotenoids (0.08489 mg leaf fresh weight) was found 60 days after spraying. The highest indicators of oxidative stress (H2O2, proline and MDA) were 5.18 micromoles gm−1, 28.71 micromoles gm−1 and 11.23 micromoles gm−1 fresh weight, respectively.