Evaluation of the growth efficiency of some citrus rootstocks for spraying melatonin growth regulator under salt stress conditions

Abstract

This research was conducted to determine the impact of spraying the increased regulator melatonin on the tolerance of some citrus roots to salt stress. The results showed that the Sour Orange root was significantly superior to the rest of the citrus rootstocks and recorded the highest increase in the rate (Height, diameter, quantity, and area of leaves for the plant), while the root Volkamer lemon was significantly the best by recording the highest rate of arid mass of the root system and plant life. Furthermore, irrigation with electrical connection water (1.7 sec.m-1) led to obtaining the highest values ​​for vegetative plant girth growth characteristics (plant girth, stem diameter, number of leaves, leaf area, dry weight of the vegetative and root system and root length). Moreover, treatment with the growth regulator melatonin at a concentration of (100 mg.L-1) showed the most significant percentage in the trait (plant height, diameter of the stem, number of leaves, size of the leaves, and dry weight of the vegetative both root system and root length). As well as the binary and triple interactions between these study factors led to a clear significant superiority in the studied traits compared to the comparison treatment, as the triple interaction treatment (Sour Orange root + melatonin at 100 mg. l-1 as the concentration+ salinity of irrigation water at a concentration of 1.7 decimens.m-1) was the most significant treatment by giving the highest increase in the rate of vegetative characteristics. Finally, the treatment (rootstocks Volkamer lemon + melatonin at 100 mg.l-1 as the concentration + salinity of irrigation water at a concentration of 1.7 dm. m-1) recorded the highest rate of length and weight of the root when it is a dry system. Keywords: melatonin; rootstocks; salinity