How can I remove the legend title in ggplot2?

Question

I have a question concerning the legend in ggplot2.

Say I have a hypothetical dataset about mean carrot length for two different colours at two farms:

Answer 1

The only way worked for me was using legend.title = theme_blank() and I think it is the most convenient variant in comparison to labs(fill="") and scale_fill_discrete(""), which also could be useful in some cases.

ggplot(carrots,aes(y=MeanLength,x=Farm,fill=Type)) + 
geom_bar(position="dodge") +
opts(
    legend.position="top",
    legend.direction="horizontal",
    legend.title = theme_blank()
)

P.S. There are more useful options in documentation.