Mitigation of drought stress effect on growth and productivity of mung bean by foliar application of sorghum water extract

Abstract

Field trial was conducted in Research Field equipped with rainfall transparent shade, Biology Department, College of Science, Baghdad University during the growing season of 2012 to test the potential of sorghum water extract in improving yield and yield components of local cultivar of mung bean crop grown under different moisture deficit stresses. The water stresses were applied by irrigated the plots to field capacity and withheld the next irrigation until the soil water deficit reaches 80, 50 and 30% of field capacity for control, mild water stress and higher water stress, respectively. Foliar application of sorghum water extract at 0 ( control), 2.5 and 5% (W/V) was made at preflowering, flowering and fruiting stages. The experiment was conducted in split plot design with four replications for each treatment. The sorghum water extract rates were kept in the sub plot while moisture deficits were assigned as main plot. Results showed that drought stress significantly reduced the averages seed yield , dry matter accumulation, number of pods per plant, number of seeds per pod and plant height. Foliar applications of sorghum extracts significantly increased seeds yield, dry weight biomass, number of seeds per pod and plant height. The interaction of drought stress and sorghum water extract treatment significantly affected seed yield , dry matter accumulation, number of pods per plant, total chlorophyll content and plant height. Application of sorghum water extract under severe moisture deficit stress (i.e., 70% field capacity) increased seed yield, dry weight biomass and plant height , number of pods per plant, number of seeds per pod by 37.8%, 48.9%,64.3%,8.7% and 5.1%, of control, respectively compared the reduction achieved by the sever moisture deficit applied alone which was 58.50% , 56.06% , 57.17% , 48.05% and 14.78 % of control for the aforementioned parameters respectively. Chlorophyll content was found to be increased by effected by application of sorghum extracts at control moisture treatment. Proline content of leaves was significantly increased by high drought stress when water extract applied alone. However, such differences disappeared when sorghum extract was applied, suggesting another mechanisms could be responsible for the stimulatory effect of sorghum extract under drought stress.