A d2 dwarfing gene in pearl millet [Pennisetum glaucum (L .) R . Br .] is currently being extensively used for the development of hybrid parents . Its effect on grain yield and yield components is poorly understood . Twelve pairs of tall and dwarf near-isogenic lines developed in the diverse genetic background of three composites were evaluated for grain yield and yield components for 2 years at two locations in southern India. The d2 gene or the genes linked to it, on an average, reduced plant height by 42%, grain yield by 14%, and head girth by 8% but increased head length and number of tillers per plant by about 5-6% . Large variations were observed among pairs (genetic background) for the difference between tall and dwarf near-isogenic lines for all of the above yield components resulting in no significant difference in five pairs and 17-35% less yield in dwarfs as compared to their tall counterparts in six pairs . Days to 50% flowering and seed weight were least affected by the d2 gene with the average difference between tall and dwarf groups of near-isogenic lines being of the order of 1-2% . These results indicate that the advantageous effects of d 2 dwarfing gene can be effectively exploited by manipulating the genetic background . The difference between the average grain yields of tall and dwarf groups of near-isogenic lines showed considerable variation across environments with the dwarfs yielding as much as tall group in one environment and up to 30% less than the tall group in the other, thus, indicating that the d2 gene effect may be substantially modified by the environments .