Effect of Rootstock and Humic Acid Spray on Lemon (Citrus lemon L.) Seedlings Tolerance to Irrigation Water Salinity

Abstract

This study was carried out in a private nursery at Baquba City, Diyala Province for the period from 24/2/2013 to 13/12/2014 to study the effect of humic acid spray on lemon (Citrus lemon L.) seedlings tolerance to irrigation with saline water .Two-Years old Lemon seedlings budded on two citrus rootstocks (Sour orange , and Swingle Cirumello) irrigated with three levels of saline water (0.7,3.0 and 4.5 dsm-1 ), and sprayed with two concentrations of humic acid (0 and 1% ).The she study Results revealed that the irrigation with the highest level of saline water(4.5 ds.m-1 )caused a significant increase in leaves proline and carbohydrates content, chlorine, sodium content and a significant decrease in chlorophyll content , while the application of humic acid at 1% resulted in a significant increase in leaves carbohydrate and chlorophyll content ,and decrease in leaves proline ,chlorine and sodium content . Seedlings budded on swingle citrumello have the superiority over that budded on sour orange in leaves carbohydrate content.