Role of salicylic acid and ascorbic acid in alleviating the harmful effects of water stress in Maize (Zea mays L.)

Water scarcity is threatening productivity of crops throughout the globe. Different osmoprotectants such as salicylic acid and ascorbic acid have potential to mitigate the harmful effects of water deficit. Current study was conducted to examine the possible role of salicylic acid and ascorbic acid individually and in combination in improving the yield and yield components of maize (Zea mays L.) exposed to drought at different growth stages. Drought was imposed by skipping irrigation at two water sensitive crop growth stages i.e. 6 fully expanded leaves (V-6 as per Feekes scale) and initiation of silking (R-1 as per Feekes scale). Water deficit significantly decreased cob diameter (19.2%), cob weight (13.8%), grain rows per cob (14.4%), cob length (12.8%), 1000-grain weight (6.2%), stover yield (17.7%), grain yield (10.6%), biological yield (8.2) as compared to normal irrigation. Drought imposed at R-1 (as per Feekes scale) was more lethal in terms of reduction in different yield and yield components including 1000-grain weight, grain yield and biological yield by 0.2, 6.9 and 0.9 %, respectively. Exogenous application of combination of salicylic acid + ascorbic acid @ 0.5mM each + tween 20 (0.1%) applied at V-6 stage (as per Feekes scale) was more effective in mitigating the harmful effects of water deficit by improving cob diameter (6%) biological yield (1%) and grain yield of maize (6.9%) as compared to drought imposed at R-1(as per Feekes scale).