Hello WouterDeCoster,
Thanks for editing my question and the answer. If I assemble forward and reverse end reads where each of them are of length 150 bp , then saying "assembling the reads of 150 bp is correct" or saying "assembling the reads of 300 bp is correct" ?
Also, I'm looking for the Denovo assemblers which can assemble reads of length 300 bp. Do you know any assemblers which can assemble reads of 300 bp?

I edited your post because you use (probably not desired) markup, e.g.
*will result in text in italics