Bains, GurdeepSudarshana Ranjan2020-10-192020-10-192020-09https://krishikosh.egranth.ac.in/handle/1/5810153320In India, maize is the third most important food crop next to rice and wheat. It is also an important industrial raw material which provides large opportunity for value addition. Waterlogging is one of the major constraints limiting maize (Zea mays L.) production, especially in the Indian subcontinent. It is commonly considered as the crop sensitive for waterlogging, where soil moisture content reaches 80 % of field capacity, maize growth and production gets severely reduced. γ-aminobutyric acid (GABA) is a small signaling molecule that accumulates rapidly in plants exposed to various stresses; allows the normal physiological metabolism under hypoxia by inhibiting the GAD activity and maintaining the balance of carbon and nitrogen. Nitrogen element is an essential element affecting crop yield, which plays main role to synthesize the photosynthetic pigments. To evaluate the efficacy of GABA and nitrogen on morphological and physiological characteristics in maize in different planting system under excess soil moisture stress condition, a field experiment was conducted during the kharif season 2019 at Norman E. Borlaug Crop Research Centre of G.B. Pant University of Agriculture and Technology, Pantnagar.The experiment consisting of two planting system, six treatment combinations of GABA and Nitrogen under ponding conditions along with non ponded condition which was laid out in factorial randomized block design with three replications. The recommended dose of nutrients was 120: 60: 40 kg N:P2O5:K2O/ha. Plant geometry was 60 cm 25 cm and crop was grown as per practice. Application of GABA and Nitrogen had significant impact on morphological and physiological parameters such as plant height, leaf area index, NDVI, chlorophyll flourescence, chlorophyll a, b, total chlorophyll, total soluble carbohydrate superoxide dismutase and malonialdehyde, grain yield, and planting system had significant impact on leaf angle,crop lodging and grain yield. All the parameters showed significant difference between ponded and nonponded condition. Research findings of this study revealed that GABA showed pronounced effect on alleviating excess soil moisture stress but for yield increasing nitrogen is more benefical under excess soil moisture. Among all treatments application of GABA + nitrogen showed best results to overcome the losses due to pondingEnglishThesis