Effect of Melatonin Spraying on some Growth Characters of Several Cotton Cultivars

Abstract

To investigate the role of melatonin on the development of certain cotton cultivars, an experiment was set up in a farmer’s fields during the summer of 2022 in the Al Karma district of the Anbar Governorate. The experiment had three replications and was set up in split plots per the RCBD protocol. The four types of cotton (Back Coat, Lachata, Coker 310, and Montana) and the four melatonin concentrations (0, 50, 100, and 150 mg L-1) were randomly distributed over the main plots. The results showed that the plants of the Coker 310 cultivar were characterized by the lowest number of nodes for the first fruiting branch on the stem and the lowest number of days to flowering, in addition to the superiority of the leaves content of chlorophyll and the highest average number of vegetative and fruiting branches, which reached 5.54 and 63.18 days and 27.26 mg 100 gm−1 fresh weight, and 3.42 and 13.51 branch plant−1 respectively. On the other hand, Back Coat plants outperformed with the highest average plant height of 170.75 cm. The cotton plants that were sprayed with a concentration of 150 mg L−1 were characterized by the lowest number of days to flowering stage (63.00 days), highest chlorophyll content in their leaves, plant height, and the number of vegetative and fruiting branches amounted to 28.50 mg, 100 gm−1 fresh weight, 185.91 cm, 3.95, and 14.70 branches. Plant−1 respectively.