Rice, grown on a wide range of soils with varying soil pH levels boron (B) availability, uptake and mobilization could be limiting hence may lead to lower productivity and rice yields has been tested at 11 locations on low yielding rice genotypes from, Initial Evaluation Trials (IET) of AICRIP viz.IET 20979, IET 21003, IET 21007, IET 21014, IET 21025 and Rasi as check variety. Active boron supplemented as foliar spray at anthesis stage at 0.2, 0.4 and 0.8 ppm. Grains with 1.20 (High density), and 1.06 (normal density) specific gravity (sp. gr.) and unfilled grains were determined. The results showed that application of boron resulted in increase in grain number (25–45) and reduced the number of unfilled spikelets. At majority of the locations, application of 0.4 ppm boron had resulted in significant increase in grain yield (4–8%). Cultures, IET 20979, IET 21007, and IET 21014 showed a positive response with the 0.4 ppm application at the majority of locations.