How do I display only selected items in a ggplot2 legend?

Question

I'm creating a stacked bar plot of relative abundance data, but I only want to display the ten most abundant organisms in the legend. How do I do this? I have no idea where to begin and haven't found any answers online.

Here's the plot with a full legend:

Thanks.

Answer 1

As pointed out by user20650 in the comments, the answer is to add a list of selected items to the breaks= argument in scale_fill_manual()

scale_fill_manual(breaks=list,values=colpal)