It is always good to have replicates, both biological and technical to increase the confidence of your results.

Prabodh Kmar, Thnk you for the answer. In case of normal plants (they are clones and don't express considerable genetic variations) both biological and technical replicates are ok. But in case of weedy plants the Technical replicates are ok but biological replicates are still confusing as every individual is genetically different from other within same population and behave differently to different environs.

Shahid, therefore biological replicates will normalize such variations and give you probably a better average or conclusions.