Researchers studied how well two types of rice, MR219 and MR269, could compete against three types of weedy rice. They grew the rice in different densities and found that weedy rice affected the growth of both cultivated rice types. As the density of weedy rice increased, the yield of MR219 and MR269 decreased. MR269 performed better in terms of yield when competing with weedy rice, especially with added nitrogen. Overall, weedy rice is stronger and can reduce the yield of cultivated rice, so it's important to control weedy rice for optimal rice production.