The exposure of plant seeds to gamma radiation is a promising prospect to crop improvement through the manipulation of their genetic makeup. Previous studies have shed light on the potential of radiation to enhance the genetic variability. In this study, we investigated the effect of gamma radiation on Pisum sativum seeds under heavy metal (nickel chloride) stress to determine the changes in morpho-biochemical attributes. Morphological parameters such as germination and photosynthetic pigments while biochemical attributes such as protein content, sugar, phenolics, and flavonoids were determined. The results showed that gamma radiation, along with (NiCl2) has a pronounced effect on plant morphology and production. In the biochemical analysis of the range from 50 Gy to 100 Gy, photosynthetic pigments and proteins were significantly associated. Although the 50 Gy dose induced a partial reduction in sugar content while the 100 Gy dose demonstrated a slight improvement relative to the 50 Gy dose. However, the phenol content increased in response to 50 Gy, whereas the flavonoid content decreased compared to the control. In combination with heavy metal (50mM) at Gy doses, the protein, sugar, phenol, and flavonoid contents showed a gradual decrease with the increase in Gy doses. In conclusion, the current study based on observations suggests that the range of gamma radiation from 50 Gy to 100 Gy is suitable for causing the mutant form of seeds. However, further studies should be conducted to determine the precise mechanism, in order to be benefitted from full potential role of gamma radiation in improving productivity under heavy metal stress.