Effect of methanol foliar application on some morph-physiological traits of sugar beet (Beta vulgaris L.) grown under drought conditions

Abstract

This study was carried out at Homs Agricultural Research Center, General Commission for Scientific Agricultural Research (GCSAR), Syria, during 2019 and 2020 winter growing seasons (mid of February), in order to evaluate the effects of methanol foliar application on some sugar beet morph physiological traits under drought stress. The experiment was carried out according to split plot arrangement using randomized complete block design with three replicates. The main factor was water deficit stress in two treatments (control and stressed), in control treatment, plants were watered well, water was cutoff 20 days before harvest, and the stressed plants were subjected to drought stress two times during growth season by withholding water 20 days during 10-12 leaf stage and 40 days before harvest. The secondary factor was the foliar application of methanol in four levels (10, 14, 18, 22 percent by volume) and 0 (control). Methanol sprayed three times with two weeks intervals, the first foliar application was applied at (10-12 leaf stage) covered all up-ground parts of plant. Results showed that all studied traits, i.e., leaf number (LN), leaf area index (LAI), relative water content (RWC), root dry weight (RDW), shoot dry weight (SDW) and total plant dry weight (TDW) were declined significantly by drought stress in both seasons, while methanol foliar application in a concentration 14-22% (v/v) reduced the negative impact of drought stress, the level of 18% (v/v) had the highest effects and lowest decrements compare to control. Increasing the concentration to 22% compare to 18% didn't led to any additive effects on morph physiological characteristics. The differences between control 0% and 10% (v/v) weren’t significant. This study concluded that methanol foliar application of 14-18 % (v/v) can be used as rich source of carbon to enhance morph physiological traits of sugar beet under optimum conditions, and to decrease the negative impact of drought stress conditions.