Pakistan is facing a severe energy crisis that is negatively impacting the whole economy as this deficiency forced local industries to move to neighboring countries. This also affects the local people losing their jobs. Due to the energy crisis, Pakistanis are forced to use tree biomass for their energy uses. This resulted in deforestation and desertification causing climate change. To combat these issues, increased afforestation of marginal and desert lands is important to meet the local demands. Prosopis juliflora is the main species of the desert where it is grown for multiple uses. This study explores mutation breeding's potential to develop useful mutants of Prosopis species. Prosopis species are characterized by low biomass, poor tree shape, small diameter, and long needles hinder their widespread adoption. Two types of mutagens i.e., physical (gamma radiation) and chemical (Ethyl methanesulfonate) were used for mutagenesis in P. juliflora and P. cineraria species. Seeds of both species were treated with three levels of mutagens i.e., low (15mM of EMS, 600Gy of gamma rays), moderate (25mM of EMS, 700Gy of gamma rays), and high (35mM of EMS, 800Gy of gamma rays). Seeds were abraded with sandpaper to enhance seed germination. LD50 for P. juliflora was 577.875±67.35 for gamma-ray and 18.732±1.80 mM for EMS. Seed germination was significantly affected in both species. However, P. cineraria proved very sensitive to both mutagens as evident by a very low seed germination thus was not suitable for mutant screening. Nevertheless, P. juliflora seed germination was significantly affected at high doses as compared to medium and low doses. P. juliflora seedlings were selected in the field for superior plant height, plant type, stem shape, and diameter as compared to the controlled seedlings. Selected seedlings were further characterized based on calorific value, lignin, cellulose, hemicellulose, moisture, fresh biomass, and dry biomass. Several superior mutants were selected with desirable characteristics for fuelwood, pulpwood, and afforestation. It is concluded that mutation breeding can be used to develop desirable mutants in a short period as compared to conventional breeding. However, future efforts must be directed to refine mutagenic doses for P. cineraria to produce a large population for mutant selection and to develop genotypes.

Keywords: Energy Crisis; Pakistan; Deforestation; Climate Change; Prosopis; Calorific Value; Tree Breeding; Genetic Diversity; Mutation Breeding