How to create separate linear and quadratic regression graphs for each group in the same panel using R?
When we draw regression lines for a group, they are usually of the same type, such as simple linear regression. Here is an example using yield data for different nitrogen rates per genotype. Then, the regression graph for each group would be shown below. I think it would be better to show the quadratic regression line for genotype A. In this case, how can we create separate linear and quadratic regression graphs for each group in the same panel? Data…