A field experiment was conducted during kharif season of 2019 at Department of Crop Physiology, Tamil Nadu Agricultural University, Coimbatore to study the influence of different plant growth regulating compounds and nutrients on biochemical changes and yield attributes of pigeonpea genotype (ICPL 11255) under irrigated condition. The treatments consist of foliar spray of growth retardants viz., mepiquat chloride @ 500 ppm and chlormequat chloride @ 500 ppm at vegetative stage and different PGRs (Salicylic acid @ 100 ppm, Brassinosteroid @ 0.1 ppm and NAA @ 40 ppm), Nutrients (ZnSO4 @ 0.5 % + Boric acid @ 0.3%, MAP @ 2% and TNAU Pulse Wonder @ 1%) and two Nutrient consortia mixtures at flower initiation and 15 days thereafter. The results revealed that, foliar application of Chlormequat chloride and Nutrient consortia -1 recorded maximum soluble protein content (15.14, 14.48 mg g-1), nitrate reductase activity (12.44, 9.01 μg NO2 g-1 h-1), maximum number of flowers plant-1 (52.30), number of pods plant-1 (18.05), 100 seed weight (11.12 g) and Fertility co- efficient (34.50 %) compared to other treatments.