Abstract; Three mutant strains Basmati 370-32, Jajai 77-30 and Sonahri Sugdasi-6 along with their respective mother varieties Basmati 370, Jajai 77, Sonahri Sugdasi and check variety Basmati 385 were evaluated under different plant population (spacings, 20 x 20 cm, 22.5 x 22.5 cm and 25 x 25cm between plant and rows) for grain yield and yield contributing parameters. An 2 2 2 increase in spacing induced vigorous plant growth as well as increased the number of panicles per hill, grain yield per hill, filled grains per panicle and 1000 grain weight. The spacing 22.5 x 22.5 cm proved more appropriate because it produced better plant 2 stand, gave more panicle density and higher grain yield than other two spacings. The mutant strains Jajai 77-30 produced significantly higher grain yield at all spacings as compared with all other entries.