Dose and genotype dependent effects of foliar acetic acid on sweet corn under water deficit

Sweet corn (Zea mays L. var. saccharata) faces significant challenges due to water deprivation caused by global water scarcity. This study investigates the potential of acetic acid to enhance sweet corn resilience by modulating morphophysiological and biochemical traits under water deficit conditions. Three genotypes were subjected to foliar application of acetic acid at altered concentrations under water deprivation. Water deprivation significantly decreased specific root and shoot length and root volume in all genotypes. However, acetic acid alleviated these adverse effects, particularly in Tyson, which exhibited a notable increase, indicating enhanced adaptability to stress. Specific leaf area increased after treatment with acetic acid; likewise, stomatal conductance showed a significant increase in Messenger and Tyson on application with acetic acid under water deprivation. Chlorophyll-a and chlorophyll-b exhibited genotype-specific and concentration-dependent responses to the treatments, with significant increases observed in Tyson with acetic acid application at 10 mM under water deprivation. Chlorophyll fluorescence parameters varied; while Messenger and GSS 8529 showed non-significant results, Tyson exhibited significant increases in actual photochemical efficiency, mainly with a low concentration of acetic acid under water deprivation. Acetic acid also reduced malondialdehyde levels, a marker of oxidative stress, across all genotypes under stress, and increased peroxidase activity in Tyson and GSS 8529, indicating enhanced antioxidant defences. These findings suggest that acetic acid application effectively mitigates the effects of water deprivation by enhancing photosynthetic efficiency, antioxidant defences, and growth parameters, showing substantial genotype differences. Further research is recommended to optimize acetic acid treatments, considering genotype-specific responses to maximize stress resilience and growth performance.