Researchers studied how different combinations of rice plants affect grain yield. They used six elite rice lines to create three crosses and measured the performance of the resulting hybrids. One cross, GNR-2 x GNR-3, showed the highest increase in grain yield compared to the parents. This cross also had more productive tillers per plant, but the weight of 100 grains decreased. Overall, the study found that some combinations of rice plants can produce better yields than their parents.