Abstract: The study is a part of tree improvement program, carried out at Biomass Research Centre, Banthra of this institute, on two fast growing leguminous tree species (Acacia nilotica and Prosopis juliflora) suitable for wood fuel production on wastelands (pH 8.6 to 10.5). It included treatment of seeds with various doses of gamma rays (10 to 50 krad) followed by layout of field trials at population density of 10,000 plants ha-1. Species performance evaluated after four years revealed differences in growth and productivity potential of plants particularly at 40 krad dose level as compared to untreated control plants. Striking variations were observed at individual tree level in treated plants for vigor and morphological traits particularly tree form (straight, bent or crooked), bole (single, forked and multiple boles), branching pattern (compact or spreading type), thorn trait (thorny, or thornless) and yield associated traits (trunk thickness and height). Selected desirable phenotypes (Candidate and Plus trees) were multiplied vegetatively through air layering, rooting of cuttings and macro-propagation technique and conserved in clonal gardens for production of quality germplasm for expanding agro-forestry plantations on stressed soils. The study revealed potential of mutation breeding in inducing greater variability without any adverse effects on plant growth of non timber species raised for short rotation in agro-forestry programs on stress soils.