In Present Continuous,for example: seviyor,biliyor,istiyor.. Is correct to not read R?

Not correct but understandable.

When writing/reading it would be considered as a mistake indeed. But most of the people do not say the Rs at the end when speaking. But we say it when speaking of ourselves. For example :

In Istanbul you would hear them saying : geliyo,gidiyo but geliyorum.
its a bit different in Anatolia                                       : geliyor,gidiyor but geliyom